the11th internationalworkshopon shipandmarinehydrodynamics ... · 3program monday,september23,2019...

The 11th International Workshop on

Ship and Marine Hydrodynamics

IWSH 2019

22 – 25 September, 2019

Hamburg University of Technology

Institute for Fluid Dynamics and Ship Theory

Hamburg, Germany

https://iwsh2019.fds.tu-harburg.de

Fluid Dynamicsand

Ship Theory

https://iwsh2019.fds.tu-harburg.de

IWSH 2019 Local Organisation Committee

Moustafa Abdel-Maksoud Hamburg University of Technology

Andrés Cura Hochbaum Technical University of Berlin

Sören Ehlers Hamburg University of Technology

Bettar el Moctar University of Duisburg-Essen

Ulf Göttsche Hamburg University of Technology

Nikolai Kornev University of Rostock

Stefan Krüger Hamburg University of Technology

Patrick Marleaux Hamburg University of Technology

Gerrit Olbert Hamburg University of Technology

Youjiang Wang Hamburg University of Technology

IWSH 2019 International Standing Committee


Jiahn-Horng Chen National Taiwan Ocean University

Atilla Incecik Strathclyde University

Masashi Kashiwagi Osaka University

Yonghwan Kim Seoul National University

Decheng Wan Shanghai Jiaotong University

IWSH 2019 International Scientific Committee


Jiahn-Horng Chen National Taiwan Ocean University

Sören Ehlers Hamburg University of Technology

Pierre Ferrant Ecole Centrale Nantes

Ismail Hakki Helvacioglu Istanbul Technical University

Chin-Yeh Hsin National Taiwan Ocean University

Changhong Hu Kyushu University

Tomoki Ikoma Nihon University

Atilla Incecik University of Strathclyde

Masashi Kashiwagi Osaka University

Yonghwan Kim Seoul National University

Dezhi Ning Dalian University of Technology

Lian Shen University of Minnesota

Sverre Steen Norwegian University of Science and Technology

Yougang Tang Tianjin University

Stephen Turnock University of Southampton

Marc Vantorre Ghent University

Decheng Wan Shanghai Jiaotong University

Chi Yang George Mason University

Zaojian Zou Shanghai Jiao Tong University

Welcome to IWSH 2019

One behalf of the international standing and local organisation committees, I

would like to warmly welcome you to the 11th Workshop on Ship and Marine Hy-

drodynamics (11th IWSH) in Hamburg. It is a great honour to be able to awaken

the spirit of the previous ten.

This workshop series was created as a platform for facilitating crucial dialogues

between young researchers and renowned scientists who have made substan-

tial contributions to the development of marine hydrodynamics and offshore en-

gineering. With this year’s strong presence of young researchers and with the

participation of leading scientists in the field, I am happy to see that we have

come much closer to attaining this goal. Knowledge exchange and transfer be-

tween young researchers and established experts is invaluable for stimulating

important research for Ship and Marine Hydrodynamics.

I hope that during the symposium you will all be able to find the time to discuss

new ideas for research and collaborations, which can then serve as material for

the next workshop.

I would like to take this opportunity to whole-heartedly thank the U.S. Office of

Naval Research Global (ONR Global) for their generous financial and logistical

support.

I would also like to thank the authors and the keynotes speaker for their important

contributions on advancing the state of numerical and experimental modelling

and the state of knowledge within our field.

The workshop’s stringent reviewing process has resulted in the highest standard

of scientific quality. For this huge effort I would especially like to thank all mem-

bers of the international standing and local committees. Many scientific journals

have approached us about reproducing selected articles from the presented pa-

pers. This is a testament to the rigorous standards of our workshop and the ex-

cellent quality of IWSH’s papers.

I wish you a successful symposium full of interesting conversations, and I bid you

welcome to the Hanseatic city of Hamburg. I hope you enjoy your stay with us.

Thank you very much

Moustafa Abdel-Maksoud

Workshop Chair

1

Contents

Contents

1 General Information 3

1.1 Venue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Lunch and Coffee Breaks . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.4 Campus Barbecue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.5 Dinner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.6 Farewell Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.7 Campus Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Information for Presenters 6

3 Program 7

4 Abstracts 14

4.1 *Invited Lectures* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.2 CFD techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.3 Design Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.4 Design for Energy Saving . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.5 Experimental Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.6 Maneuvering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.7 Marine Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4.8 Numerical and Statistical Methods . . . . . . . . . . . . . . . . . . . . 45

4.9 Offshore Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

4.10Offshore Wind Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

4.11Wave Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

4.12Wave Induced Motions and Loads . . . . . . . . . . . . . . . . . . . . . 62

5 Notes 69

2

1 General Information


1.1 Venue

The workshop will take place in building H on the main campus of Hamburg Uni-

versity of Technology. Please find address and GPS coordinates below. There is a

campus plan on page 5.

Hamburg University of Technology

Am Schwarzenberg-Campus 5 (H)

21073 Hamburg

GPS: 53◦ 27′ 44.3′′ N 9◦ 58′ 10.5′′ E (53.462306, 9.969583)

1.2 Registration

The Registration Desk is located in the foyer of Building H. The first chance to

register is during the Welcome Reception on Sunday from 17:00 - 19:00. Receive

your name badge and conference materials at the desk and get in touch with

the other participants. A variation of drinks and finger-food will be served. If you

arrive later, don’t worry. The Registration Desk will be open every day during the

workshop hours to welcome newly arriving participants and help out if there are

any questions. On Monday morning registration is possible from 7:30 onwards.

1.3 Lunch and Coffee Breaks

A catering station will be located in the foyer of Building H and provide you with

beverages and food during the workshop breaks. Seating possibilities are ar-

ranged in the rooms nearby. There will be a sound signal indicating the end of

each break. Please make sure to enter the seminar rooms in time.

3

https://www.google.com/maps/place/53.462306, 9.969583



1.4 Campus Barbecue

Amongst students and research staff of TUHH it is very popular to get together

for a barbecue at the end of a work day. This is why we think that a barbecue on

the campus would be the perfect setting to round off the workshop’s first day full

of scientific content. The event will take place on Monday evening (17:30) next

to the campus lake, which is only a few meters away from the venue. Take a look

at the plan on page 5.

1.5 Dinner

On Tuesday evening we invite you to a festive dinner at the restaurant Zeitlos.

The restaurant is located in the Harburger Binnenhafen, which is the city districts

own port area. Enjoy the maritime flair paired with delicious food and live jazz

music. Fine wines, beer and various alcohol free drinks are included as well. The

dinner will start at 19:00 and come to an end at 23:00. Please find address and

GPS coordinates below. If you like to walk to the dinner location together, please

meet with our staff members at 18:30 in the lobby of Hotel Panorama or BnB Hotel

respectively.

Zeitlos Events

Harburger Schloßstr. 22

21079 Hamburg

GPS: 53◦ 27′ 51.5′′ N 9◦ 59′ 06.4′′ E (53.464297, 9.985123)

1.6 Farewell Reception

On Wednesday afternoon the workshop will come to an end. We would like to

say goodbye in the foyer of Building C, which is only a few meters away from the

venue. Beverages and finger-food will be available.

4



1.7 Campus Plan

1.7 Campus Plan

5

2 Information for Presenters

2 Information for Presenters

This page provides information regarding your presentation in order to avoid

technical problems and ensure a smooth procedure in the presentation sessions.

Please read the following lines thoroughly. If you have any questions during the

workshop, don’t hesitate to ask the on-site technical staff.

You may either use your own laptop or the one provided in the session rooms.

We recommend to use a screen ratio of 16:9 for your presentation. Both rooms

feature beamers with VGA and HDMI connections. Please bring an adapter, if your

laptop has another output. The laptops provided have Microsoft Office 2016 and

Adobe Acrobat Reader DC installed.

Please report to the technician desk in the back of the respective session room

during the break at least two sessions before your presentation, to

• transfer and test your presentation, if you use the on-site laptop. Please

have the presentation on a USB flash drive with you.

• Check the connection, if you intend to use your own laptop.

• Receive instructions regarding the procedure and the technical equipment.

For a good audibility of your presentation, you will be using a headset. Please

come to the technician desk in the back of the session room at least 10 minutes

before your presentation, to allow the technical staff to attach and adjust the

microphone.

The presentations shall be at most 20 minutes. The remaining ten minutes are

reserved for questions from and discussions with the audience. It is very impor-

tant to stay within the time limits, so that the overall workshop schedule can be

maintained.

6

3 Program

3 Program

On the following pages the workshop program is presented. The program of each

day is printed on a double page. Below is a table of days with the corresponding

first page number.

Monday, September 23, 2019 8

Tuesday, September 24, 2019 10

Wednesday, September 25, 2019 12

7

3 Program

Monday, September 23, 2019

07:30 - 08:30

Registration

Foyer H

08:15

-

08:30

H 0.16

Opening Session

08:30

-

09:30

H 0.16

Invited Lecture (Chair: Bettar el Moctar)

Sloshing Analysis for Liquid Cargo Design of Ships and Floating Structures [89]

Yonghwan Kim

SNU, NAOE, KOR

09:30 - 10:00

Morning Coffee/Tea

10:00

-

12:00

H 0.16

Wave Dynamics (Chair: Yonghwan Kim)

H 0.01

CFD techniques (Chair: Nikolai Kornev)

A Modified Model for Waves Generated by

a Moving Body in a Stratified Fluid with

Free Surface [6]

Yuhang Li, Ke Chen, Yunxiang You

SJTU, NAOCE, CHN

Numerical Simulation on Influencing Fac-

tors of High Speed Water Entry [45]

Shiming Sun, Kai Yan, Xiaohui Wang, Guangtao

Liu, Xuesen Chu

CSSRC, CHN

Damping of Non-Linear and Irregular Long-

Crested Free-Surface Waves Using Forcing

Zones [17]

Robinson Perić, Moustafa Abdel-Maksoud

TUHH, FDS, DEU

Numerical Study of Sloshing Motion on Un-

structured Mesh Using UMTHINC [19]

Mohamed M. Kamra, Changhong Hu

KU, RIAM, JPN

Diffraction of Wavefront around Cylinders

[43]

Ruipeng Li, Xiaobo Chen, Wenyang Duan

HEU, Shipbuilding Eng, CHN

Estimation of Flows around a Full-Scale

Ships by Structured Overset RaNS Code

“NAGISA” [80]

Nobuaki Sakamoto, Hiroshi Kobayashi, Kunihide

Ohashi

NMRI, JPN

Quantitative Evaluation of Temporal Varia-

tion for the Short-Crested Irregular Wave

Generated in Experimental Wave Basin

[60]

Daichi Ota, Takako Kuroda, Hidetaka Houtani

NMRI, JPN

RANS Model for Bow Wave Breaking of

a KRISO Container Ship under Different

Speeds [72]

Anzheng Yu, Decheng Wan

SJTU, NAOCE, CHN

12:00 - 13:00

Lunch

8

3 Program

Monday, September 23, 2019

13:00

-

14:30

H 0.16

Offshore Wind Turbine (Chair: Motoki Araki)

H 0.01

Design for Energy Saving (Chair: Changhong

Hu)

Experimental and Numerical Study for

Weathervane and Stability Performance

of Single-Point-Moored FOWTs Under

Wind-Current Coexisting Field [9]

Kazuki Hashimoto(1), Sharath

Srinivasamurthy(1), Kazuhiro Iijima(2), Yasunori

Nihei(1)

(1)OPU, MSE, JPN, (2)Osaka University, NAOE,

JPN

Development of Air Lubrication System for

Reduction of Ship Frictional Drag [82]

Sangmin Kim, Jinhak Kim, Soonho Choi

SHI, KOR

Craneless Upending of Large Offshore

Monopiles Using A Specialised Floater

[18]

Pascal Voges(1), Axel Nernheim(2), Marc

Seidel(2), Christian Schulz(1), Moustafa

Abdel-Maksoud(1)

(1)TUHH, FDS, DEU, (2)SGRE, DEU

The CFD Study of Rudder-Bulb-Fin System

in Changing Cambered Foil and AOA Ap-

plied to KVLCC2 Tanker [32]

Quang Tho Truong, Yasuyuki Toda

Osaka University, NAOE, JPN

Coupled Response Analysis of an Offshore

Articulated Wind Turbine under Different

Environmental Loads [3]

Pei Zhang, Yougang Tang

TJU, CHN

Study of Trim Optimization Based on De-

sign of Experiments and RANS Simulation

[66]

Jianwei Chen(1), Cheng Yu(2), Liang Shen(2)

(1)SJTU, NAOCE, CHN, (2)Seastel, CHN

14:30 - 15:00

Afternoon Coffee/Tea

15:00

-

17:00

H 0.16

Offshore Wind Turbine (Chair: Moustafa

Abdel-Maksoud)

H 0.01

CFD techniques (Chair: Robinson Perić)

Dynamic response of a novel reduced draft

Spar-type FOWTwith anti-motion damping

structure [31]

Pei Zhang, Yan Li, Yougang Tang

TJU, CHN

Numerical Simulations of Viscous Flows

around JBC Ship Using Different Turbu-

lence Models [73]

Jianhua Wang, Decheng Wan

SJTU, NAOCE, CHN

Numerical Analysis of A Floating Horizon-

tal Axis Tidal Current Turbine with Sway

Motion [30]

Chen Zeng, Moustafa Abdel-Maksoud

TUHH, FDS, DEU

VπLES– Vortex Particle Intensified Large

Eddy Simulation [54]

Nikolai Kornev(1), Sina Samarbakhsh(2)

(1)URO, LeMoS, DEU, (2)URO, DEU

LES Study of Wind Turbine Wake Mean-

dering in the Atmospheric Boundary Layer

[69]

Xu Ning, Decheng Wan

SJTU, NAOCE, CHN

A Linearized Free-Surface RANS Method

for Self-Propulsion and Maneuvering [77]

Paolo Geremia(1), Kevin Maki(2), Pavlos Alexias(3)

(1)ENGYS, ITA, (2)UMICH, NAME, USA, (3)ENGYS,

GBR

Planar Motion Modeling of Full-Scale SUB-

OFF in Deep and Unlimited Water [65]

Yu-Cheng Hsu, Chi-Yu Chen, Sheng-Hsuan Chiu,

Shiu-Wu Chau

NTU, ESOE, TWN

Numerical Simulation of Ship Motion and

Life Boat Launch using Overset Mesh [49]

Alok Khaware(1), Vinay Kumar Gupta(1), Hemant

Punekar(1), Patrick Sharkey(2)

(1)ANSYS, USA, (2)ANSYS UK, GBR

17:30 - 20:00

Campus Barbecue

TUHH lake

9

3 Program

Tuesday, September 24, 2019

08:30

-

09:30

H 0.16

Invited Lecture (Chair: Decheng Wan)

Simulation of Cavitating Turbulent Flows [88]

Milovan Perić

UDE, ISMT, DEU

09:30 - 10:00

Morning Coffee/Tea

10:00

-

12:00

H 0.16

Wave Induced Motions and Loads (Chair:

Andrés Cura Hochbaum)

H 0.01

Experimental Methods (Chair: Jun Zhang)

CFD Analysis of Ship Oblique Towing in

Waves [11]

Zhang Zhu, Jae-Hoon Lee, Yonghwan Kim

SNU, NAOE, KOR

Flow Visualization of Horseshoe Vortices

around a Surface-Mounted Hydrofoil [59]

Chun-Yao Yang, Yaw-Huei Lee, Yi-Chih Chow

NTOU, SENA, TWN

Numerical Study on Steady Wave Drift

Forces of an Obliquely Moving Ship [20]

Wei Zhang(1), Ould El Moctar(2)

(1)UPC, CHN, (2)UDE, ISMT, DEU

Application of Pendulum Theory to a Model

of the Overturning of a Rectangular Hull in

a Water Tank [48]

Yuji Doya, Tatsuo Sawada

Keio Uni., Dept. Mech. Eng., JPN

Quick Evaluation of Seakeeping Perfor-

mance for Ship Hull Form Optimization

[67]

Jinkai Wang, Decheng Wan

SJTU, NAOCE, CHN

Experimental Investigation of Vortex-

Induced Vibrations Using 3DAccelerome-

try and Digital Image Correlation [76]

Simon Tödter(1), Hassan el Sheshtawy(2), Jens

Neugebauer(2), Ould El Moctar(1)

(1)UDE, ISMT, DEU, (2)UDE, DEU

Analysis of the Second Order Wave Forces

Acted on a Floating Pontoon [79]

Yuji Miao(1), Xujun Chen(1), Haipeng Shen(1),

Xiao Wei(1), Kai Lu(1), Guanghuai Wu(2)

(1)PLAAEU, CFE, CHN, (2)NGETLTD, CHN

Experimental study of an oscillating buoy

Wave Energy Converter coupled with a

floating breakwater [74]

Junhua Zhan(1), Xiaofeng Kuang(1), Yang Ni(1),

Wenhui Zheng(1), Xiongbo Zheng(2)

(1)CSSRC, CHN, (2)HEU, CHN

12:00 - 13:00

Lunch

10

3 Program

Tuesday, September 24, 2019

13:00

-

14:30

H 0.16

Wave Induced Motions and Loads (Chair: Xi-

aobo Chen)

H 0.01

Design Optimization (Chair: Yasuyuki Toda)

Comparative Study on Different CFD

Solvers for Analysis of Ship Added Resis-

tance [14]

Byung-Soo Kim(1), Kyung-Kyu Yang(2), Zhang

Zhu(1), Yonghwan Kim(1)

(1)SNU, NAOE, KOR, (2)KRISO, KOR

Hull Form Optimization to Lower Resis-

tance in Still Water and Added Resistance

in Waves [56]

Hao Hao, Weimin Chen, Chuanqing Li

SSSRI, CHN

Experimental Study on Hydrodynamic

Forces Acting on Ship Hull and Rudder

behind the Propeller in Regular Waves

[33]

Van Minh Nguyen(1), Seo Ju Won(1), Yeon-Gyu

Kim(2), Hyeon Kyu Yoon(1)

(1)CWNU, CWNU, KOR, (2)KRISO, KOR

Fully Automatic Design Space Exploration

by RANS Computations [68]

Sebastian Uharek(1), Stefan Harries(1), Andres

Cura Hochbaum(2)

(1)Friendship, DEU, (2)TUB, DMS, DEU

Experimental and Numerical Evaluation of

the Added Wave Resistance for an Ultra

Large Container Ship in Shallow Water.

[75]

Luca Donatini(1), Manases Tello Ruiz(1), Guil-

laume Delefortrie(2), José Villagómez(2), Evert

Lataire(1), Marc Vantorre(1)

(1)UGent, MTD, BEL, (2)FHR, BEL

A Mooring Arrangement Optimisation

Study [22]

Thibaut Van Zwijnsvoorde(1), Marc Vantorre(1),

Evert Lataire(1), Katrien Eloot(2)


14:30 - 15:00

Afternoon Coffee/Tea

15:00

-

17:00

H 0.16

CFD techniques (Chair: Milovan Perić)

H 0.01

Marine Propulsion (Chair: Jun Ando)

Numerical and Test Analysis for Resistance

and Self-Propulsion Performance of a Trail-

ing Suction Hopper Dredger [10]

Zhigao Luo, Long Yu

SJTU, NAOCE, CHN

The Underwater Noise Reduction of Pump-

jet Propulsor using Sawtooth Duct with dif-

ferent Inclination Angles [15]

Denghui Qin, Guang Pan, Shi Yao, Qiaogao

Huang

NWPU, KLUUV, CHN

A Numerical Investigation of the Turbulent

Flow around a Scale Model JBC Hull us-

ing the Generalized k-omega (GEKO) Tur-

bulence Model [16]

Patrick Sharkey(1), Florian Menter(2)

(1)ANSYS UK, GBR, (2)ANSYS Germany, DEU

SPIV Measurement for a Self-propelled

Ship in Regular Head Waves with Different

Amplitudes [41]

Benson Oyunge Mwangi, Haruki Nango, Ya-

suyuki Toda

Osaka University, NAOE, JPN

Turbulent Mixing Analysis of Discharge

Streams for Open-loop Exhausted Gas

Cleaning System [28]

Yung-An Chu, Tsung-Yueh Lin

CR, TWN

Scale Effect on the Hydrodynamic Perfor-

mance of a Ducted Propeller under Consid-

eration of Flow Transition and Cavitation

[87]

Erik Schomburg(1), Moustafa Abdel-Maksoud(2)

(1)SVA Potsdam GmbH, DEU, (2)TUHH, FDS, DEU

A Computational Study for Flow past a

Junction with a Strake [29]

You-Sheng Lin, Jiahn-Horng Chen

NTOU, SENA, TWN

Different techniques to simulate tandem

propeller with boundary element method

[64]

Youjiang Wang(1), Ulf Göttsche(1), Moustafa

Abdel-Maksoud(1), Stefan Krüger(2)

(1)TUHH, FDS, DEU, (2)TUHH, SSI, DEU

19:00 - 23:00

Symposium Dinner

Restaurant Zeitlos

11

3 Program

Wednesday, September 25, 2019

08:30

-

09:30

H 0.16

Invited Lecture (Chair: Jiahn-Horng Chen)

A Potential Method for Fully Non-Linear Wave Responses of Ships [1]

Heinrich Söding

TUHH, FDS, DEU

09:30 - 10:00

Morning Coffee/Tea

10:00

-

12:00

H 0.16

Offshore Structures (Chair: Tatsuo Sawada)

H 0.01

Maneuvering (Chair: Heinrich Söding)

Study on The Truncation Factor of Moor-

ing System for a Ultra-deep Water Plat-

form [55]

Zhang Feng wei, Kuang Xiaofeng, Wu Lan, Fan

Yali, Zhao Zhanhua

CSSRC, CHN

Investigation of Training Data Selection in

the Black-box Modeling of Ship Maneuver-

ing Motion [8]

Zihao Wang, Carlos Guedes Soares, Zaojian Zou

SJTU, NAOCE, CHN

Numerical Analysis of Vortex-Induced

Yaw Motion of a Paired-Column Semi-

Submersible in Currents [70]

Weiwen Zhao, Decheng Wan

SJTU, NAOCE, CHN

Simulation of WIGS Dynamic Derivatives in

Viscous Flow [38]

Fu Xing, Nianfu Zhou, Haijie Dong

CSSRC, CHN

CFD Simulations andModel Experiments of

Offshore Support Vessel with Heavy Sus-

pended Load in Waves [4]

Motoki Araki(1), Kazuhisa Otsubo(1), Kei Ishida(1),

Kenta Hasegawa(1), Hiroshi Sato(1), Kunihide

Ohashi(2)

(1)NMRI, OE, JPN, (2)NMRI, JPN

An Energy-Efficient Adaptive Course Con-

trol System for Ocean Surface Ships [52]

Changyuan Chen(1), Manases Tello Ruiz(1), Guil-

laume Delefortrie(2), Marc Vantorre(1), Evert

Lataire(1)


Wave-Induced Motions of Moored and Cou-

pled Multibody Offshore Structures [85]

Grusche Seithe, Ould El Moctar

UDE, ISMT, DEU

Adaptive Target Tracking of the Under-

way Replenishment in Consideration of the

Hydrodynamic Interaction between Two

Ships [57]

Yi Liu(1), Zhi-Hua Zeng(2), Zaojian Zou(2), Shem-

ing Fan(1), Peiyuan Feng(1)

(1)MARIC, CHN, (2)SJTU, NAOCE, CHN

12:00 - 13:00

Lunch

12

3 Program

Wednesday, September 25, 2019

13:00

-

15:00

H 0.16

Numerical and Statistical Methods (Chair:

Zaojian Zou)

H 0.01

Marine Propulsion (Chair: Youjiang Wang)

Application of Precise Integration Method

for structure dynamics in hydroelasticity

computation [46]

Zhe Sun

DUT, SNAOE, CHN

On Cavitation Nuclei Measurments - A

State of the Art [83]

Ernst August Weitendorf

TUHH, DEU

Sensitivity Analysis for Ship Squat Predic-

tions using Sobol’ Indices [5]

Li Xia, Zaojian Zou, Zihao Wang

SJTU, NAOCE, CHN

Numerical analysis of unsteady hydrody-

namic performance of pump-jet propulsor

in oblique flow [7]

Chengcheng Qiu(1), Guang Pan(2), Qiaogao

Huang(2), Shi Yao(2)

(1)NWPU, SMST, CHN, (2)NWPU, KLUUV, CHN

Software-In-the-Loop Method to Predict

the Global Dynamic Responses of Full-

scale Floating Wind Turbines by Artificial

Neural Network [40]

Peng Chen

NU, Engineering, GBR

Numerical Investigation of Cavitation and

Hydrodynamic Characteristics of Damaged

Propeller [71]

Minsheng Zhao, Decheng Wan

SJTU, NAOCE, CHN

Prediction on Extreme Distribution of

Sloshing Loads Considering Various Statis-

tical Models and Threshold Values [13]

Jeougkyu Lee, Jieung Kim, Yangjun Ahn, Yongh-

wan Kim

SNU, NAOE, KOR

Hydrodynamics and Vortex Structure of

Undulating Fins in Stationary Water [86]

Zhang Jun, Bai Yaqiang, Zhai Shucheng, Gao De-

bao, Su Boyue

CSSRC, CHN

15:30 - 17:00

Farewell reception

Foyer C

13

4 Abstracts

4 Abstracts

On the following pages, the abstracts of the workshop presentations are printed.

They are sorted by topics. Inside each topic the abstracts are sorted by the paper

number given in brackets behind the title.

*Invited Lectures* 15

CFD techniques 17

Design Optimization 25

Design for Energy Saving 27

Experimental Methods 30

Maneuvering 34

Marine Propulsion 38

Numerical and Statistical Methods 45

Offshore Structures 49

Offshore Wind Turbine 52

Wave Dynamics 57

Wave Induced Motions and Loads 62

14

4.1 *Invited Lectures*

4.1 *Invited Lectures*

A Potential Method for Fully Non-Linear Wave Responses of Ships [1]

Heinrich Söding

Hamburg University of Technology, Fluid Dynamics and Ship Theory, Germany

Abstract A potential method is described to compute responses of ships in steep waves.

All substantial nonlinear effects are taken into account. Compared to field methods solving

Euler or Rans equations, it is much faster. The method is verified by comparing its results

for motions and loads in longitudinal and oblique waves with those of field methods, other

potential methods and model experiments.

Keywords potential method, seakeeping, ship response, steep wave

Simulation of Cavitating Turbulent Flows [88]

Milovan Perić

University of Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and

Transport Systems, Germany

Abstract Most commercial and public CFD-codes include cavitation models and simula-

tions of cavitating flows are a commonplace nowadays in many areas of engineering, in-

cluding offshore and shipbuilding industries. In this presentation we first describe the three

main approaches to modeling cavitation: homogeneous two-phase flow (Euler-Euler), bub-

ble dynamics (Euler-Lagrange) and VOF with phase change at the interface. The advantages

and disadvantages of each class of models are addressed. We then focus on discussion of

modeling errors and their interaction with other sources of errors (modeling of turbulence,

accuracy of geometry details, roughness effects, grid fineness etc.). Disagreement between

experiment and simulation is often attributed to a wrong cause and we want to emphasize

the importance of trying to distinguish contributions from each source of possible errors from

each other. This is especially important when simulating tip-vortex cavitation, where adap-

tive mesh refinement around the vortex core leads to an enormous improvement in results;

turbulence model also significantly affects this type of cavitation. This will be demonstrated

using examples of public propeller tests with the Potsdam propeller test case (PPTC). Issues

of practical relevance like incipient cavitation and cavitation-induced erosion will also be

addressed. Example simulations will be used to highlight the topics of discussion.

15

4 Abstracts

Sloshing Analysis for Liquid Cargo Design of Ships and Floating

Structures [89]

Yonghwan Kim

Seoul National University, Department of Naval Architecture and Ocean Engineering,

South Korea

Abstract Sloshing analysis is one of main elements in the design of the ships and floating

platforms which have partially filled liquid tank(s), such as LNG carriers and FLNG platforms.

Sloshing-induced impact can cause the local or global failure of cargo structure, therefore

such risk has been of great concern for ship designers. In past 15 years, Seoul National Uni-

versity(SNU) has carried out many research projects related to sloshing problem, including

model experiments, computational analyses, hydroelasticity experiments for LNG insulation

system, the coupled analysis of ship motion and sloshing, and prediction of sloshing loads

based on data mining and machine learning scheme. In this presentation, some represen-

tative model tests for typical and non-typical shapes of liquid cargo will be introduced, and

their results will be shown. Also, important technical issues in practical sloshing analysis

will be mentioned. For model tests, the issues related to pressure sensor, materials of liq-

uid and gas, and phase transition will be explained. For the prediction of sloshing loads, the

methods for statistical analysis, prescreening for experimental conditions, and application

of machine learning scheme using SNU’s pressure database will be mentioned. In addition,

some results of CFD computation and motion coupling will be also introduced.

16

4.2 CFD techniques

4.2 CFD techniques

Numerical and Test Analysis for Resistance and Self-Propulsion

Performance of a Trailing Suction Hopper Dredger [10]

Zhigao Luo, Long Yu

Shanghai Jiao Tong University, School of Naval Architecture, Ocean & Civil Engineering,

China

Abstract Resistance and self-propulsion performances of trailing suction hopper dredger

(TSHD) remains a hot issue in predicting and improving performances of TSHD. In this paper,

the CFD simulation technology and overset technology are used to calculate the resistance

performance of TSHD at different velocities, and the results are accord with the model test

results. Then overset technology is used to calculate the self-propelled performances of

THSD equipped with different propellers under different working conditions. The results are

consistent with the tests results. The performances between two kinds of propellers are

compared and analyzed through field analysis.

Keywords Propeller

A Numerical Investigation of the Turbulent Flow around a Scale Model

JBC Hull using the Generalized k-omega (GEKO) Turbulence Model [16]

Patrick Sharkey(1), Florian Menter(2)

(1)ANSYS UK Ltd, United Kingdom,(2)ANSYS Germany GmbH, Germany

Abstract In this investigation, qualitative comparisons with experimentally obtained PIV

and LDA data from a scale-model wind tunnel facility are made with numerical solutions

obtained using CFD for the Japan Bulk Carrier (JBC) geometry using a new 2-equation turbu-

lence model, the Generalized k-omega (GEKO) model. Distributions of relevant quantities

such as local velocity, local vorticity and local turbulence quantities at specific locations

in the near-stern region are compared in both straight-ahead and pure-drift configurations.

Grid dependence studies for various types of unstructured mesh are conducted to assess

the sensitivity of the results to grid type and grid resolution.

Keywords Computational fluid dynamics, Japan Bulk Carrier, Turbulence Model

17

4 Abstracts

Numerical Study of Sloshing Motion on Unstructured Mesh Using

UMTHINC [19]

Mohamed M. Kamra, Changhong Hu

Kyushu University, Research Institute for Applied Mechanics, Japan

Abstract The numerical simulations of sloshing motions are performed for different test

cases with various filling levels and oscillation frequencies. The numerical results are an-

alyzed and compared with experimental data. The numerical computations are performed

with a Volume Of Fluid (VOF) based Reynolds-Averaged Navier-Stokes (RANS) solver. Our

in-house numerical solver employs the unstructured multi-dimensional tangent hyperbolic

interface capturingmethod (UMTHINC) for free-surface capturing combined with various tur-

bulence models. The sloshing motion is numerically modeled using the body-force method

which introduces a source term into the momentum equation corresponding to the tank

motion profile.

The numerical results of impact pressure and free-surface are compared with published

experimental data wherever possible. The effect of turbulence model choice on loading

predictions is highlighted by studying several RANS models and analyzing its effect on fluid

motion and impact pressure. The effect of tank internal structures is studied by considering

two approaches: finite thickness approach and zero-thickness approach. The developed

solver is able to accurately capture the complex interface structure without smearing even

with long time integration. The results showed a favorable agreement of impact pressure

as well as the general fluid motion.

Keywords Computational fluid dynamics, RANS, Sloshing load, THINC, Volume of Fluid

18

4.2 CFD techniques

Turbulent Mixing Analysis of Discharge Streams for Open-loop

Exhausted Gas Cleaning System [28]

Yung-An Chu, Tsung-Yueh Lin

CR Classification Society, Taiwan

Abstract Due to IMO regulations on sulphur oxides (SOx) emissions after 2020, exhaust

gas cleaning systems (EGCS) or equivalent measures are commonly being adopted on ships.

For open-loop type SOx scrubbers, one of the requirements is that, during commissioning

of the EGC unit, the pH-value of the discharged wash water plume shall be no less than

6.5, measured 4 meters externally from the ship at rest, verified either by means of direct

measurement or by using CFDmethod. A uniform jet inlet from a circular hole into stationary

water was built up using Star-CCM+, to conform with a cited experimental setup. The grids

were carefully adjusted to resolve the core region of turbulent mixing at the jet nozzle.

The axial velocity profiles at several positions were in good agreement with the experiment

results. Also the universal dispersion angle of the jet envelope cone, where the axial velocity

is zero, was correctly demonstrated to be about 12 degrees. The volume fraction of wash

water and seawater was traced via the passive scalar method, which was then converted

to pH-value by using the standard titration curve of seawater. The iso-contour of pH-value

equal to 6.5 was captured so as to determine its distance from the discharge point. The

test case also included a configuration with an inducer and diffuser mounted at the end of

the discharge pipe, which showed considerable effects on the mixing performance and the

length of streams.

Keywords SOx scrubber, Turbulence Jet

19

4 Abstracts

A Computational Study for Flow past a Junction with a Strake [29]

You-Sheng Lin, Jiahn-Horng Chen

National Taiwan Ocean University, Department of Systems Engineering and Naval

Architecture, Taiwan

Abstract A strake is a practice device to install in front of a wing-body junction to sup-

press horseshoe vortex. In this paper, we designed a strake for a finite wing mounted on a

flat plate. The flat boundary layer passes the wing with zero angle of attack. The wing is

composed by a 3:2 ellipse and the NACA 0020 section. They join together at the maximum

thickness. The profile of the strake on the plane of symmetry is a part of a generalized el-

lipse. The cross sections of the strake on the flat plate is also a part of an ellipse. The cross

section at y > 0 is of the same form as the one on the flat plate but is shifted rightwards

so that the left vertex coincides with the generalized ellipse. Some sets of values of the

strake length and height were chosen for study. The flow was first studied computational

via RANS equations. The solutions which show no horseshoe vortex were then picked. And

then the LES computations were employed to investigate the detailed flow characteristics.

The solution by RANS computations represents time-averaged one and that by LES compu-

tations depicts the instantaneous features of the flow. The comparison will be presented in

the paper.

Keywords Horseshoe vortex, Junction flow, LES, RANS

20

4.2 CFD techniques

Numerical Simulation on Influencing Factors of High Speed Water Entry

[45]

Shiming Sun, Kai Yan, Xiaohui Wang, Guangtao Liu, Xuesen Chu

China Ship Scientific Research Centre, China

Abstract The accurate prediction of high speed water entry is very crucial for the re-

search on improving the penetration abilities of underwater vehicles. In this paper, the

water entry problem of an axisymmetric blunt vehicle with velocities ranging from 200m/s

to 600m/s are numerically studied based on the CFD method. Firstly, the accuracy of the

numerical method was verified by experiments. Secondly, the influence of water compress-

ibility on the water entry is studied and it is found that the compressibility will affect impact

loads of water entry but has little influence on cavity shapes. Thirdly, the numerical results

of cavity shapes during early stages of water entry are compared with the theoretical results

based on the principle of independence of the cavity sections expansion. It is found that

the numerical results of cavity shape are generally agreed with theoretical results except

for the parts near the water surface. Lastly, the main similarity parameters for high speed

water entry are also analysed and it is concluded that Mach number is the most important

similarity parameter during early stages of water entry at this range of velocities. The re-

sults of this paper could provide some guide for the numerical simulations and scaled tests

of high-speed water entry.

Keywords CFD, cavity, similarity rule, water compressibility, water entry

21

4 Abstracts

Numerical Simulation of Ship Motion and Life Boat Launch using

Overset Mesh [49]

Alok Khaware(1), Vinay Kumar Gupta(1), Hemant Punekar(1), Patrick Sharkey(2)

(1)ANSYS Inc, United States,(2)ANSYS UK Ltd, United Kingdom

Abstract Marine systems need to be designed for performance and safety. Numerical

simulations are extensively used to aid this design process. These simulations involve com-

plexities associated with free surface flowmodelling along with moving bodies. To overcome

some limitations of the traditional dynamic mesh approach, in the present work overset

mesh approach has been employed, which provides ease of mesh generation and mod-

elling of mesh motion. Two common marine hydrodynamic problems are simulated using

the Volume of Fluid method (VOF) and overset approach. The first problem focuses on the

dynamic response of a container ship at open sea. Accurate prediction of the ship response

to the wave plays an important role as it may add resistance altering the speed of the ship or

may compromise the structural integrity. The steady-state free surface simulation around

the KRISO container ship (KCS) hull is performed where water elevation on the ship and

resistance coefficient are validated against experiment. Transient simulation is performed

on full-scale KCS hull model where ship interaction with the head wave is captured using a

5th order Stokes wave theory and six-degree of freedom solver. The heave and pitch mo-

tion of the ship is validated against the published data. The second problem focuses on the

launching of a lifeboat in the calm water. The lifeboat gets high acceleration due to free

fall and the impact point during water entry becomes an important consideration for the

safety of passengers. Injury potential of an occupant is directly linked with the acceleration

ratio of the boat and the maximum limiting values are recommended by the International

Maritime Organization (IMO). Transient simulation for the lifeboat launching is performed

where acceleration and boat motion profile are studied in detail.

Keywords CFD, KCS Hull Simulation, Lifeboat Launch, Overset Mesh

22

4.2 CFD techniques

VπLES– Vortex Particle Intensified Large Eddy Simulation [54]

Nikolai Kornev(1), Sina Samarbakhsh(2)

(1)University of Rostock, LeMoS, Germany,(2)University of Rostock, Germany

Abstract The paper presents a novel LES like method which is based on the decompo-

sition of the flow structures in large scale ones, resolved on the grid, and small scale ones,

represented by grid -free vortex particles. Validation and verification procedure is performed

for free jet case.

Keywords Computational fluid dynamics

Numerical Simulations of Viscous Flows around JBC Ship Using

Different Turbulence Models [73]

Jianhua Wang, Decheng Wan


China

Abstract High Reynold number (Re) viscous flow is one of the most typical characteris-

tics of an advancing ship. Therefore, the wake flow after the ship hull is very complex and it

will strongly affect the propulsion performance. RANS approach and hybrid LES/RANS meth-

ods are very popular in the contemporary research of ship flows, with the consideration of

less computational cost compared with LES. In the present work, several numerical mod-

els, i.e. standard Shear Stress Transport (SST) model for RANS, DES, Delayed DES (DDES)

and Improved Delayed DES (IDDES) model are used to predict the viscous flows around a

full block ship. Numerical computations are carried out by the in-house CFD solver naoe-

FOAM-SJTU developed on OpenFOAM. The ship model Japan Bulk Carrier (JBC) is used in the

present computations and the numerical setup is following the benchmark case in Tokyo

2015 CFD Workshop. Extensive experimental data including detailed wake flows through

PIV measurements is available for the validation of the CFD results. Predicted results of ship

resistance, wake flow in different cross sections are presented and compared with the exper-

imental data. The results based on different DES approaches are discussed and compared

with the RANS results. It is found that the IDDES method can improve the performance in

predicting turbulence features. Good agreement with experimental results shows that the

RANS approach can give good prediction of the resistance, while IDDES approach is more

suitable in predicting the complex viscous flows around full block ship hull.

Keywords IDDES, JBC ship, Ship wake flow, turbulence models

23

4 Abstracts

A Linearized Free-Surface RANS Method for Self-Propulsion and

Maneuvering [77]

Paolo Geremia(1), Kevin Maki(2), Pavlos Alexias(3)

(1)ENGYS, Italy,(2)University of Michigan, Department of Naval Architecture and Marine Engineering,

United States,(3)ENGYS, United Kingdom

Abstract Numerical prediction of the hydrodynamical performance of unsteady ship op-

erations, such as selfpropulsion and maneuvering, is an important method to help naval ar-

chitects design optimal ship hulls. Currently, traditional finite-volume Computational Fluid

Dynamics (CFD) methods offer a well-proven simulation platform to realize such predictions

with a high degree of accuracy. In this work, a novel transient CFD method based on an

unsteady linearized free-surface RANS solver is presented for the objective of simulating

ship maneuvering. The specific results presented in the paper are for the self-propulsion

and turning circle of the Korean Containership KCS. The results achieved, show that the new

linearized free-surface RANS solver provides a viable and more cost-effective alternative

than traditional Volume-of-Fluid (VOF) methods. The key new developments highlighted in

this paper are in the way that self-propulsion is included and a new robust mesh motion

method to handle the relative motion of the rudder.

Keywords Maneuvering, PMM, Propeller, RANS, Rudder, resistance

Estimation of Flows around a Full-Scale Ships by Structured Overset

RaNS Code “NAGISA” [80]

Nobuaki Sakamoto, Hiroshi Kobayashi, Kunihide Ohashi

National Maritime Research Institute, Japan

Abstract National Maritime Research Institute has recently developed in-house viscous

CFD solver “NAGISA”. It solves Reynolds averaged Navier-Stokes (RaNS) equation in block-

structured grid based finite volume manner with free surface and several turbulence mod-

els. The code has the capability of handling multi-body problem with statically/dynamically

overlapped grids for which the domain connectivity information is calculated by the in-house

overset grid assembler UPGRID. The major purpose of the present study is to investigate

NAGISA’s capability to solve flows around ships in full scale. Several merchant ships are

subjected to the computation, and available experimental data in model scale as well as

the measured data in full scale are utilized to validate the computational results.

Keywords CFD, full scale, overset grid

24

4.3 Design Optimization

4.3 Design Optimization

A Mooring Arrangement Optimisation Study [22]

Thibaut Van Zwijnsvoorde(1), Marc Vantorre(1), Evert Lataire(1), Katrien Eloot(2)

(1)Ghent University, Maritime Technology Division, Belgium,(2)Flanders Hydraulics Research, Belgium

Abstract Ports want to ensure safe and reliable loading operations for all ships. Increase

in ship sizes, especially container ships, can potentially cause unsafe mooring situations.

For ships moored at quay walls, there is also a lack of international guidelines and recom-

mendations for mooring arrangements. This paper presents a case study for a moored con-

tainership being passed by a vessel of identical dimensions. The behaviour of the moored

ship is simulated using UGent’s time-domain mooring software Vlugmoor. Starting from a

well-balanced arrangement used currently in daily operation, three optimisation steps are

presented, aimed at lowering the ship motions, which are critical. The first step explores the

impact of changing line positioning to reduce line length disparity and improve efficiency

in critical force directions. The second step considers a lower fore mooring deck to reduce

line steepness, as well as additional winches below the bridge and funnel. The third step

proposes replacing medium stiff lines with a very stiff HMPE line, combined with an elastic

tail. The effect of these optimisation steps on the ship motions are presented and compared

with predictions based on efficiency parameters. These factors express the capability of the

configuration to deal with positive and negative surge forces. It is shown that applying these

optimisation steps can significantly improve the safety of a moored container ship during a

ship passage.

Keywords efficiency parameters, moored vessel safety, mooring arrangement, passing

vessel effect

25

4 Abstracts

Hull Form Optimization to Lower Resistance in Still Water and Added

Resistance in Waves [56]

Hao Hao, Weimin Chen, Chuanqing Li

Shanghai Ship and Shipping Research Institute, China

Abstract In order to improve operating economy of a container ship, its hydrodynamic

performance is improved by optimizing bow and stern hull-forms with parametric hull form

generation method. Different optimization algorithms are deployed to obtain the optimum

hull form at the condition of design draft and design speed when displacement is defined as

a basic constraint. The paper uses STARCCM+ to calculate the resistance in still water, while

added resistance is calculated by STF strip method. By comparing the numerical results, a

satisfying hull form can be found. Both powering performance and seakeeping performance

are improved.

Keywords Added resistance in wave, calm water resistance, parametric hull form gen-

eration

Fully Automatic Design Space Exploration by RANS Computations [68]

Sebastian Uharek(1), Stefan Harries(1), Andres Cura Hochbaum(2)

(1)Friendship Systems AG, Germany,(2)Technical University Berlin, Dynamics of Maritime Systems, Germany

Abstract The present paper presents the result of a design space exploration study for

three design variables performed for a twin screw ROPAX ship performed with the Computer

Aided Engineering (CAE) software CAESES and the RANS code Neptuno using the meshing

software GridPro for the automatic generation of the computational grid for each design

iteration step. The design space exploration is carried out using an ensemble design engine,

which performs a systematic variation of the parameters in the desired design space. After

the exploration, the results are used to set up a surrogate model for a subsequent fast

optimization. It can be shown that the current approach allows an easy and fully automatic

generation of a reliable surrogate model once the parametric model, the grid topology and

the numerical computations are set up.

Keywords CAESES, Design space exploration, RANS, Response surface

26

4.4 Design for Energy Saving


The CFD Study of Rudder-Bulb-Fin System in Changing Cambered Foil

and AOA Applied to KVLCC2 Tanker [32]

Quang Tho Truong, Yasuyuki Toda

Osaka University, Naval Architecture and Ocean Engineering, Japan

Abstract The present research is to develop the fin geometry based on an available

rudder designed for KVLCC2 tanker in order to achieve a Rudder-Bulb-Fin system that op-

erates with lowest drag as well as highest possible propeller efficiency. The cambered foil

that is used in this research is cambered 4-digit airfoil as a design of the National Advisory

Committee for Aeronautics (NACA). The camber-line and thickness have been adjusted and

simulated by using CFDSHIP-IOWA code to be able to find out the optimal energy-saving

devices. The change of attack angle is also combined through obtaining its benefit from

previous designs. The improvement of rudder-bulb-fin system will be discussed in detail in

this paper. The total resistance by these designs could be reduced a significant amount of

percentage and improved the propulsive efficiency in comparison with previous designs.

Keywords Computational fluid dynamics, ship resistance

27

4 Abstracts

Study of Trim Optimization Based on Design of Experiments and RANS

Simulation [66]

Jianwei Chen(1), Cheng Yu(2), Liang Shen(2)

(1)Shanghai Jiao Tong University, School of Naval Architecture, Ocean & Civil Engineering,

China,(2)Seastel Marine System (Shanghai) Co. Ltd., China

Abstract Trim optimization is a particularly easy and cheap way of improving ship per-

formance, reducing fuel oil consumption and lowering emission. The purpose of trim opti-

mization is to obtain the optimal trim to minimize the ship total resistance at the specified

draft and speed. The usual approach is to establish a surrogate model to estimate the ship

resistance based on some sample points. However, for most of present practices of trim

optimization, a large number of sample points are uniformly distributed in the design space

composed of draft, trim and speed. As a result, a high computing cost can be expected. In

this paper, the design of experiments (DOE) is introduced to reduce the number of sample

points. Each sample point contains the ship resistance at a specified draft, trim and speed.

Then ordinary kriging interpolation is utilized to construct the surrogate model. The ship

resistances at the conditions of the sample points are achieved by RANS simulations and

the KCS model is selected in the present research. The accuracy of the surrogate model

is verified by other RANS simulations. Results indicate that DOE and ordinary kriging inter-

polation can reduce considerable calls for the CFD solver and remain the accuracy of the

surrogate model approximately.

Keywords RANS simulation, Trim optimization, design of experiments, kriging interpola-

tion

28


Development of Air Lubrication System for Reduction of Ship Frictional

Drag [82]

Sangmin Kim, Jinhak Kim, Soonho Choi

Samsung Heavy Industries Co., Ltd, South Korea

Abstract Frictional resistance occupies a large portion of the total resistance of a vessel

accounting for nearly 60 8̃0%, and lower friction resistance can lead to a remarkable reduc-

tion in greenhouse gas (GHG) emissions from ships. Air lubrication is widely recognized as

one of the useful technologies to reduce a ship’s frictional resistance by injecting air to cover

a large portion of wetted hull surface. In present study, first, the effects of injected air layer

on the skin frictional drag are investigated through various experiments and relevant analy-

sis on a flat plate and model ships. Then, particular air lubrication systems for two full scale

ships are designed, and their performance are validated by the data obtained during actual

voyages. A heavy cargo carrier and an LNG carrier are selected for the full scale applications,

whose results have been derived from a joint development project with the participation of

a shipyard, ship owners and a certification body. The amount of fuel saving through the

application of the air lubrication system is evaluated by analyzing operation data acquired

during sea trials and actual voyages in service. The installed air lubrication system on the

bottom of the ship hull is found to be effective for the reduction of the fuel oil consumption.

The overall efficiency of the air lubrication system can be further improved by optimizing

the size and location of the air injectors, which are deemed as the two important parame-

ters for optimum design of the air lubrication system. This paper discusses the experience

gained in applying the air lubrication technology to the full scale ships, and demonstrates

the effectiveness of the air lubrication for reducing fuel consumption of ships

Keywords Air lubrication, Energy saving, Frictional resistance

29

4 Abstracts

4.5 Experimental Methods

Application of Pendulum Theory to a Model of the Overturning of a

Rectangular Hull in a Water Tank [48]

Yuji Doya, Tatsuo Sawada

Keio University, Department of Mechanical Engineering, Japan

Abstract This paper reports on an experimental study of applying pendulum theory to

determine whether a rectangular model of a hull would overturn. A pontoon used as a

non-self-navigating work vessel was considered in this study. Its model begins to list when

an unbalanced load is applied. It can then either stabilize in an inclined state or continue

overturning, throwing the unbalanced load midway, and finally stabilizing in the inverted

position. In a mid-air experiment, this correlation was made between two motion scenarios,

pendular or rotational motion. The two motions were reproduced by changing the distance

between the hull center and the rotary axis and the mass of the weight. The experimental

results closely matched those of an analytical analysis performed based on the Runge-Kutta

method, which confirms the validity of the proposed analysis.

Keywords assembly hull, floating body, fluctuation, knockdown pontoon, module hull,

pendulum theory, rectangular hull, rolling, stability, turnover

30


Flow Visualization of Horseshoe Vortices around a Surface-Mounted

Hydrofoil [59]

Chun-Yao Yang, Yaw-Huei Lee, Yi-Chih Chow

National Taiwan Ocean University, Department of Systems Engineering and Naval

Architecture, Taiwan

Abstract The horseshoe vortex (HSV) usually induces undesirable effects like noise, vi-

bration, and drag. Therefore, the HSV is not only of academic interest but also a criti-

cal engineering issue. We used two high-speed cameras with prolonged exposure time to

record the pathlines of the seeding particles illuminated by a continuous-wave laser. These

particle pathlines constitute a very clear visualization of flow structures, especially vortical

structures, i.e. vortices. Next, we used this PIV-based flow visualization technique to study

the kinematics of HSV associated with a surface-mounted NACA66 hydrofoil for a Reynolds

number of 8,820 (based on the maximum thickness of the hydrofoil and the free-stream

velocity). We observed six kinematic patterns of HSV, and measured the occurrence prob-

ability for each pattern: (i) steady (17%), (ii) amalgamating (26%), (iii) breakaway (31%),

(iv) transition (12%), (v) random (8%), and (vi) roll-up (6%). The naming and definitions of

patterns (i) to (v) are adopted from Younis et al [1]. We also found that the HSV adjacent to

the hydrofoil surface rises as it extends downstream.

Keywords Coherent structure, Flow visualization, Horseshoe vortex, Kinematic pattern

31

4 Abstracts

Experimental study of an oscillating buoy Wave Energy Converter

coupled with a floating breakwater [74]

Junhua Zhan(1), Xiaofeng Kuang(1), Yang Ni(1), Wenhui Zheng(1), Xiongbo Zheng(2)

(1)China Ship Scientific Research Centre, China,(2)Harbin Engineering University, China

Abstract A newwave energy converter (WEC) system coupled with a floating breakwater

is introduced in this paper. To analyse the dynamic performance of the WEC, an experiment

device was designed and tested in two different basins. The independent experiment was

conducted in a Seakeeping basin which focused on the performance of single WEC and the

influence of the reflected wave. In the joint experiment, the WEC device was installed on the

floating breakwater, the power generation efficiency and motion of the joint platform was

measured in a deepwater offshore engineering basin. A PTO system was used for measuring

the power generating efficiency. The following conclusions are drawn from the comparison

experiment: (a) The superstition of incident wave and the reflected wave of the floating

breakwater could increase the power generation efficiency and the motion of the WEC ex-

cept some short wave. In several short-wave condition, the overtopping wave impacted on

the top of the buoy caused the reducing of the power generation efficiency. (b) The rela-

tive motion of the buoy and the floating breakwater is larger than independent experiment

condition especially in long wave which increase the power generation efficiency.

Keywords backplane, floating breakwater, oscillating buoy, wave energy converter

32


Experimental Investigation of Vortex-Induced Vibrations Using

3DAccelerometry and Digital Image Correlation [76]

Simon Tödter(1), Hassan el Sheshtawy(2), Jens Neugebauer(2), Ould El Moctar(1)

(1)University of Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and

Transport Systems, Germany,(2)University of Duisburg-Essen, Germany

Abstract Tower structures of wind turbines are often installed in various configurations at

the port before being transported by ships. Vortex-induced vibrations may occur when the

natural frequency of the structure is close to flow vortex shedding frequency. This leads to a

considerable reduction of their fatigue life. The phenomenon is well-known for risers in the

oil and gas industry. Here, we present an experimental study of vortex-induced vibrations

(VIV) of a fully and partially submerged hollow cylinder in water. A circulating water channel

generated the flow towards the test bodies. Two hollow cylinders with a length-to-diameter

ratio (l/d) of 28.13 and 18.5 and an outer diameter of 32mm were used. Each cylinder was

equipped with three-dimensional accelerometers. From the acceleration data, a two-fold in-

tegration delivered the motion amplitudes of the cylinders at the location of the accelerom-

eter. In addition, a speckle pattern was applied to the cylinders and captured with two

high-speed cameras, arranged in different orientations to the cylinder. Three-dimensional

Digital Image Correlation (DIC) was used to measure the motion trajectories for the areas of

the cylinder, covered by a speckle pattern. First, decay tests for the test bodies were per-

formed in air and water. From the motion trajectories, the natural frequencies and damping

coefficients were evaluated. Second, tests in uniform flow were conducted under fully and

partially submerged conditions for different flow velocities. Flow effects such as reduced

velocity on vibration were assessed in terms of motion amplitudes and frequencies in lon-

gitudinal and transverse direction. The results from DIC and accelerometer measurements

were compared and the suitability of DIC for VIV investigations was discussed.

Keywords Digital Image Correlation, Experimental Methods, Vortex Induced Vibration

33

4 Abstracts

4.6 Maneuvering

Investigation of Training Data Selection in the Black-box Modeling of

Ship Maneuvering Motion [8]

Zihao Wang, Carlos Guedes Soares, Zaojian Zou


China

Abstract For the identification modeling of ship maneuvering motion, comparisons be-

tween various training data are conducted to select appropriate excitation signal with max-

imum dynamic information, thereby ensuring the generalization ability of the identified

model. The identification framework is black-box modeling based on the (“nu”)-support

vector machine algorithm with radial basis function kernel, which automatically controls

the number of support vectors and keeps sparsity. A Mariner class ship is taken as the

study object, and the training data is generated from the reliable simulation model, in-

cluding 10º/10º, 20º/20º, 30º/30º zigzag maneuvers and 35º turning circle maneuver. The

generalization performance of the identified model under different training data is com-

pared by predicting other standard zigzag and turning maneuvers. The results indicate that

the 20º/20º and 30º/30º zigzag maneuvers contain more dynamic information and can be

used to train the model when the data is pure. The present work provides guidance for the

subsequent experiment research to update the ship model quickly in the field.

Keywords Identification Modelling, Multiple Excitation Signals, Ship Manoeuvring, Sup-

port Vector Machine

Simulation of WIGS Dynamic Derivatives in Viscous Flow [38]

Fu Xing, Nianfu Zhou, Haijie Dong


Abstract Wing in ground effect vehicle is a type of the latest high performance vehicles.

Due to the strong nonlinear change of aerodynamics with flight altitude and wind direction

always being parallel in wind tunnel, the important aerodynamic derivative to climb angle

is hardly to be tested. In this paper, a theoretical method of acquiring partial dynamic

derivative of the wing in ground effect vehicle is derived by using the forced vibration of

WIG vehicle above a certain flying height. At the same time, the aerodynamic characteristics

of WIGS of XTW series are analyzed by means of fluent code using the theoretical method

developed. It is shown that the numerical simulation method is reasonable compared with

the experimental value, and the theoretical method of acquiring partial dynamic derivative

of the wing in ground effect vehicle is feasible.

Keywords CFD, Effect, Ground, Wing, aerodynamic, derivative

34

4.6 Maneuvering

An Energy-Efficient Adaptive Course Control System for Ocean Surface

Ships [52]

Changyuan Chen(1), Manases Tello Ruiz(1), Guillaume Delefortrie(2), Marc Vantorre(1), Evert

Lataire(1)


Abstract In order to improve the performance and the energy efficiency (rudder actions)

of the ship control system in presence of changing environmental conditions and system un-

certainty, this paper develops a novel adaptive fuzzy-PID course controller with a dynamic

compensator and a nonlinear feedback for the autonomous surface ship. Firstly, an adaptive

PID control strategy, whose control parameters are real-time adjusted by the fuzzy system,

is designed to achieve the optimal control effect and the robust performance. Then, con-

sidering the uncertainty and unpredictable external disturbances, the Least Square Sup-

port Vector Machines (LSSVM) approach is employed to online identify and suppress the

disturbances for the purpose of compensating the Fuzzy-PID controller. Furthermore, the

nonlinear feedback is added in the control law to deal with the control inputs, and then the

whole control system is named as “NFPL”. The effectiveness and quality of the designed

controller are investigated in the numerical simulations. Results demonstrate good adapt-

ability and robust performance of the designed control system in spite of the existence of

the time-varying environmental disturbance, and the advantages in the reduction of the

settling time and rudder energy consumption as well as fast response are also verified.

Keywords NFPL controller, dynamic compensator, energy efficient, nonlinear feedback

35

4 Abstracts

Adaptive Target Tracking of the Underway Replenishment in

Consideration of the Hydrodynamic Interaction between Two Ships

[57]

Yi Liu(1), Zhi-Hua Zeng(2), Zaojian Zou(2), Sheming Fan(1), Peiyuan Feng(1)

(1)Marine Design and Research Institute of China, China,(2)Shanghai Jiao Tong University, School of Naval Architecture, Ocean & Civil Engineering,

China

Abstract Underway replenishment is a common way for ship supply at present, and the

manual manipulation is the usual mode in the present, which would be greatly affected by

the helmsman’s experience. It is expected that the automatic control mode will become the

main mode in the future. During the process of ship underway replenishment, interaction

disturbances between two ships exist, which should be accounted for controller design. In

this paper, the ship-to-ship hydrodynamic interactions are analyzed by using Computational

Fluid Dynamics (CFD) method. The influences of transversal and longitudinal distance be-

tween two ships on the hydrodynamic interactions are illustrated. The details of the flow

filed, such as pressure distributions on the two ship hulls and wave patterns are discussed to

get a deeper insight into the physical flow mechanism during the underway replenishment.

Then the ship motion model in consideration of the hydrodynamic interactions between two

ships of underway replenishment is presented. The model predictive control (MPC) technol-

ogy is adopted to control the yawmotion. To minimize the cross-track error and compensate

for the drift effect caused by the hydrodynamic interactions between two ships, the integral

line of sight (ILOS) guidance law is used for generating the desired heading angle. Finally,

the computer simulations are conducted to evaluate the efficiency of the controller.

Keywords CFD, adaptive target tracking, ship to ship interaction, underway replenish-

ment

36

4.6 Maneuvering

Planar Motion Modeling of Full-Scale SUBOFF in Deep and Unlimited

Water [65]

Yu-Cheng Hsu, Chi-Yu Chen, Sheng-Hsuan Chiu, Shiu-Wu Chau

National Taiwan University, Dept. of Eng. Sci. and Ocean Eng., Taiwan

Abstract This paper proposes a numerical approach to predict the planar motion of a

full-scale SUBOFF as well as its hydrodynamic coefficients in deep and unlimited water,

where the free surface and wall effects are neglected. The Euler’s equations of motions

are employed to describe the underwater motion of a body in deep submergence. Due to

the geometrical features of the studied hull form, a simplified form of motion equations is

obtained through ignoring minor equation terms in the case of planar motions. A linear

approach is further adopted to estimate the added mass and damping coefficients of the

submerged vessel, where the coefficients of main components of vessel, such as hull, sail,

sail fin, stern fin, and rudder, Fig.1, are separately evaluated and then integrated into the

simplified motion equations. The turbulent flow around these components are numerically

calculated to predict their hydrodynamic coefficients, where a grid-independent solution is

predicted via a successive grid refinement of the computational domain. The solution of

the simplified motion equations is based on a time-marching scheme. An iterative method

is first used to solve the simplified motion equations at a given instance and a first-order

projection method is then employed to predict the position and status of the vessel at the

next time step.

Keywords CFD, SUBOFF, Ship motion modeling, hydrodynamic coefficients

37

4 Abstracts

4.7 Marine Propulsion

Numerical analysis of unsteady hydrodynamic performance of pump-jet

propulsor in oblique flow [7]

Chengcheng Qiu(1), Guang Pan(2), Qiaogao Huang(2), Shi Yao(2)

(1)Northwestern Polytechnical University, School of Marine Science and Technology, China,(2)Northwestern Polytechnical University, Key Laboratory for Unmanned Underwater

Vehicle, China

Abstract This works builds a pump-jet propulsor model with DTRC4119 propeller data.In

order to improve the accuracy of the numerical simulation, the pump-jet propeller adopts all

structured grid and full-channel simulation .Analysis of the variation of the load factor of the

pump-jet propeller with different oblique flow angles and different advance coefficients.The

exciting forces of the pump-jet propulsor is calculated, the peak value of the pulsating com-

ponents of the six components of the bearing force is obtained. And the fluctuating pressure

peak of the pump-jet propulsor influenced by the distribution of the fluctuating pressure at

the different monitoring points and different oblique inflow angles are analyzed.

Keywords Other aspects of hydrodynamics in ship and ocean engineering

The Underwater Noise Reduction of Pumpjet Propulsor using Sawtooth

Duct with different Inclination Angles [15]

Denghui Qin, Guang Pan, Shi Yao, Qiaogao Huang

Northwestern Polytechnical University, Key Laboratory for Unmanned Underwater Vehicle,

China

Abstract The sawtooth duct noise reduction technology is used for underwater noise

reduction of Pumpjet Propulsor (PJP). Flow around the PJP is solved using Detached-Eddy-

Simulation (DES) model, while noise is predicted based on Ffowcs-Williams and Hawkings

equation. Results show that the sawtooth duct can reduce the sound pressure level of PJP

over the frequency range 100-5000 Hz, although it will result in water efficiency loss at low

J cases. The sawtooth duct makes the axial velocity distribution of PJP outflow more uniform

and reduces the TKE value at the wake region of PJP. The maximum water efficiency is

reduced about 2% by sawtooth duct, and the open water efficiency at low J case gradually

decreases with the increase of the sawtooth inclination angle. Significantly, the sawtooth

duct reduce the overall sound pressure level about 3.82-7.17 dB, while causes the efficiency

loss about 1.67%-2.56% at the design point. The sawtooth duct with sawtooth inclination

angle 10°has the most great noise reduction about 7.17 dB with only 1.93% openwater

efficiency loss at the design point of PJP.

Keywords Propeller

38


SPIV Measurement for a Self-propelled Ship in Regular Head Waves

with Different Amplitudes [41]

Benson Oyunge Mwangi, Haruki Nango, Yasuyuki Toda

Osaka University, Naval Architecture and Ocean Engineering, Japan

Abstract In this study, the wave amplitude dependency on a ship advancing in regular

head waves with different amplitudes is investigated by Experimental Fluid Dynamics (EFD)

method. The thrust, towing force and 3DOF (Degree of Freedom) motions as well as the

flow field around the stern of KVLCC2 (KRISO Very Large Crude-oil Carrier2) tanker model

advancing at design Froude number, Fr=0.142 are measured. Three wavelengths; λ/L=1.1,

1.6 and 2 are selected and for each wavelength five different wave amplitudes; A=0.75, 1.5,

3, 4 and 4.3 are used. The motions and force measurement was done for with and without

propeller conditions whereas the SPIV (Stereo-Particle Image Velocimetry) measurement

was done for without propeller condition.

The motions and force measurement results were analyzed by Fourier series expansion and

the data was reconstructed by ignoring the higher harmonics than 7th harmonics to under-

stand the fluctuation shape in one period. It was noted that the 1st, 2nd and 3rd harmonic

components are responsible for the thrust oscillations with a quickly increasing slope and a

slowly decreasing slope. For motions, the 1st harmonic components were enough to obtain

the original motion trend. The 1st harmonic values for heave and pitch motions increase

linearly with increase in wave amplitude. On the other hand, the thrust mean values de-

crease slightly with increase in wave amplitude. For the PIV results, the vertical relative

motion between the propeller disk and the low velocity region, due to bilge vortices, was

observed. As the wave amplitude increases this relative motion increases and high velocity

flow enters the propeller plane from the bottom.

In conclusion, the velocity distribution around the stern was analysed and discussed with re-

spect to the thrust fluctuation in waves. The trend could be explained although the velocity

field was measured for without propeller condition.

Keywords EFD, Flow Field, KVLCC2, SPIV, Wave Amplitude Dependency

39

4 Abstracts

Different techniques to simulate tandem propeller with boundary

element method [64]

Youjiang Wang(1), Ulf Göttsche(1), Moustafa Abdel-Maksoud(1), Stefan Krüger(2)

(1)Hamburg University of Technology, Fluid Dynamics and Ship Theory, Germany,(2)Hamburg University of Technology, Institute of Ship Design and Ship Safety, Germany

Abstract In this work, the boundary element method (BEM) has been used to calculate

the open water performance of a tandem propeller with our in-house solver panMARE. Sim-

ulating such multi-stage marine propulsors involves handling the interaction between the

rear blades and the wake sheets of front blades. The wake sheet and blade geometry can

intersect, which may lead to singularity and incorrect pressure distribution. Different tech-

niques are proposed to allow a simulation without singularity. The results obtained with

these techniques are presented, and their advantages and disadvantages are discussed.

Keywords Boundary Element Method, Tandem Propeller

40


Numerical Investigation of Cavitation and Hydrodynamic

Characteristics of Damaged Propeller [71]

Minsheng Zhao, Decheng Wan


China

Abstract In the present study, a numerical simulation of cavitation flows around a dam-

aged and a complete four –bladed E779A propeller has been carried out. The numerical

results can be used as a reference to evaluate the working ability of a propeller in case of

damage. In numerical simulation, the damaged propeller is simplified as the INSEAN E779A

propeller missing one blade, hence, it’s a three-bladed. The typical unsteady dynamics are

predicted by the RANS method with a modified shear stress transport (SST) k-ω turbulence

model. The numerical results such as cavitation shape, pressure distribution and the thrust

coefficient Kt are analysed and compared with each other, to investigate the influence of

propeller damage. The numerical calculations of non-cavitating flow are obtained using

pimpleFoam. The results of open water characteristics are basically in accordance with

experimental data, the error is about 6%, indicating the reliability of the present method.

Then the cavitation flow simulations are solved by InterPhaseChangeDyMFoam in the open

source CFD software platform OpenFOAM with Schnerr-Sauer cavitation model. It can be

noted that the propeller with a missing blade output less thrust, and the influence of the

asymmetry of the three-blade propeller on the cavitation and open water characteristics is

also obvious. The disturbance of cavitation flow to pressure variation is also the reason for

the reduction of propeller thrust coefficient. With the change of advance coefficient, this

influence will be strengthened.

Keywords Cavitation, Damaged propeller, Open water characteristics

41

4 Abstracts

On Cavitation Nuclei Measurments - A State of the Art [83]

Ernst August Weitendorf

Hamburg University of Technology, Germany

Abstract The knowledge on cavitation nuclei as part of the water quality and its influence

on the cavitation process forms the subject of this survey review. The personal experiences

and view of the author as well the general understanding of this special field play a sub-

stantial role. At beginning of the introduction the formulation of a cavitation number by

Thoma is mentioned and the one by Ackeret is presented. Regarding the physical process

of cavitation Eisenberg explained that cavitation inception is connected to microbubbles

which serve as cavitation nuclei . Following the introduction, chapter 2 describes the first

attempts of cavitation nuclei measurements at cavitation model propeller tests with the

laser scattering light technique (LSL) according to Keller and also holography investigations

carried out by scientific coworkers from the Third Physical Institute of the University Göt-

tingen (Prof. Lauterborn). The next chapter, i. e. no 3, mentions the development and

first PDA (Phase Doppler Anemometry) measurements with model propellers. This made

it particularly clear that the nuclei concentration of different cavitation tunnels depend on

their dimensions. Chapter 4 summarizes comparative nuclei measurements initiated by the

cavitation committee of the ITTC (International Towing Tank Conference) at the beginning of

the 1990-s. In chapter 5 the Interferometric Particle Imaging Technique (IPI) is mentioned

which treats a closer examination of optically occurring glare points on micro bubbles. This

chapter also shows cavitation CFD simulations using PDA-measured micro bubbles as input

data. Finally, chapter 6, i. e. the conclusion summarizes advantages of the IPI Technique

and discusses the problem whether solid particles can be cavitation nuclei. Also possibilities

for determining cavitation nuclei by holography are addressed.

42


Hydrodynamics and Vortex Structure of Undulating Fins in Stationary

Water [86]

Zhang Jun, Bai Yaqiang, Zhai Shucheng, Gao Debao, Su Boyue


Abstract The fishes swim with high efficiency and low noise, gives us important enlight-

enment on propulsor design. The Gymnarchus Niloticus Fish (GNF) swimming by a long

undulating dorsal-fin generally cruises with high efficiency and extra-ordinal manoeuvrabil-

ity while keeping its body for the straight line. In the paper the hydrodynamics and vortexes

structure of undulating fins in stationary water are calculated by Large Eddy Simulation(LES)

and dynamic grid technique with diffusion-based smoothing model. The thrust produced by

undulating fins is measured at wave amplitude of 850, and the unsteady flow field around

undulating fins on the middle cross section and mid-sagittal plane at wave amplitude of

850 is measured by phase-locked Particle Image Velocimetry(PIV) in the stationary water.

The thrust calculated by numerical simulation is in good agreement with hydrodynamics ex-

periments. The vortex structure and its evolution on cross sections and mid-sagittal plane

calculated by LES qualitatively agree well with PIV experiments. The vortexes structure and

mechanism of hydrodynamics generation are analyzed.

Keywords bionic propulsion, undulating fins, vortex structure

43

4 Abstracts

Scale Effect on the Hydrodynamic Performance of a Ducted Propeller

under Consideration of Flow Transition and Cavitation [87]

Erik Schomburg(1), Moustafa Abdel-Maksoud(2)

(1)Schiffbau-Versuchsanstalt Potsdam GmbH, Germany,(2)Hamburg University of Technology, Fluid Dynamics and Ship Theory, Germany

Abstract The paper presents the numerically investigated scale effects / Reynolds num-

ber effects for a 4-bladed ducted propeller under consideration of flow transition and cavi-

tation in open water test conditions. The RANS calculations were made with the ANSYS CFX

solver using the Explicit Algebraic Reynolds stress models (EARSM) turbulence model partly

in combination with the γ-Reθ transition model and the Rayleigh-Plesset cavitation model.

To separate different Reynolds number effects the work was divided into different scopes.

In the first scope the general behaviour of flow transition was calculated for a NACA66Amod

2D hydrofoil section and a simplified 3D hydrofoil in a neutral duct. The results show that

the critical Reynolds number for flow transition for a 2D and a 3D hydofoil increases com-

pared to the flat plate transition Reynolds number. The negative pressure gradient of the

hydrofoil stabilizes the boundary layer and therefore leads to a longer laminar zone com-

pared to the flat plate transition. The transition develops more gradually without a sudden

flow transition. A second scope shows the calculated scale effect to the duct characteristic

of a Wageningen 19A duct driven by an actuator disc. It could be shown, that the duct

force and the tip vortex are influenced by the boundary layer distribution. These general

flow behaviour characteristics were checked for a 4-bladed propeller in a Wag. 19A duct

as a third scope. A significant scale effect to the thrust-torque ratio of the ducted propeller

could be observed for Re < 5∙106̂. At the lower loaded propeller operating points significant

Reynolds number influence on the thrust breakdown was calculated.

Keywords Cavitation, Ducted Propeller, Flow Transition, RANS CFD, Reynolds number

effect, Scale effect

44

4.8 Numerical and Statistical Methods


Sensitivity Analysis for Ship Squat Predictions using Sobol’ Indices [5]

Li Xia, Zaojian Zou, Zihao Wang


China

Abstract Ship’s sinkage, trim and resistance will increase when entering shallow waters.

It is of great significance to investigate the squat of ship in shallow and confined navigation

areas. However, there aremany factors affecting the ship’s squat, such as speed of the ship,

block coefficient, water depth and draught of the ship et al. In this paper, the contribution

of these factors to the squat is measured in empirical formula models using Sobol’s indices

which is a useful method to quantify the respective effects of input random variables onto

the variance of the response of a physical or mathematical model. Results are obtained

from six empirical models, Barrass, Eryuzlu, Huuska, Yoshimura, Romisch and Ankudinov,

demonstrating that the speed of the ship has significant influence while the shape of the

bow/stern, single/twin propeller have little effect on the squat of the hull.

Keywords empirical formula, sensitivity analysis, sobol indices, squat

45

4 Abstracts

Prediction on Extreme Distribution of Sloshing Loads Considering

Various Statistical Models and Threshold Values [13]

Jeougkyu Lee, Jieung Kim, Yangjun Ahn, Yonghwan Kim


South Korea

Abstract A study on the sloshing load estimation is becoming more active as the de-

mand of LNG carrier is increasing. Interests in numerical approach to sloshing phenomenon

are increasing due to the development of computer performance and calculation methods.

However, due to the strong nonlinearity of sloshing flow, up to now, experimental stud-

ies are more dominant and more reliable. These experimental results are widely used for

sloshing load estimation and numerical simulation.

The impact pressure values obtained through the sloshing model test are used to estimate

the design sloshing load through statistical processing. At this time, the estimated maxi-

mum impact pressure values are highly dependent on the statistical model applied to the

experimental results. In the short term prediction, the difference of the estimated values

according to the statistical model is not large, but in long term prediction, the difference of

the estimated values increases according to the selection of the statistical model.

In this study, the peak-over-threshold method is applied to investigate the influence of the

threshold used in the statistical analysis of sloshing loads. Weibull distribution, generalized

Pareto distribution, and log-logistic distribution are used to the statistical analysis. In addi-

tion to the previously used moment method, the parameters of distributions are estimated

using the L-moment method and the maximum likelihood function estimation. Statistical

analysis is performed based on the experimental data obtained from 20 repeated experi-

ments of 5 hours in real scale. In order to compare the results between statistical models,

the probability plot correlation coefficient and the 3-hour most probable maximum are used.

The results of this study can be one of the indicators for the statistical analysis for sloshing

load prediction according to experimental conditions.

Keywords Extreme statistics, Impact pressure, Sloshing, Sloshing load

46


Software-In-the-Loop Method to Predict the Global Dynamic Responses

of Full-scale Floating Wind Turbines by Artificial Neural Network [40]

Peng Chen

Newcastle University, School of Engineering, United Kingdom

Abstract The design of floating offshore wind turbines (FOWTs) need accurate predic-

tions of full-scale global dynamic responses. Conventional basin experimental method can

hardly be used directly to predict the full-scale global dynamic responses of FOWTs, due

to the dissimilarity of aerodynamic load and hydrodynamic load. Besides, numerical sim-

ulation methods are not reliable enough at this moment due to the lack of full-scale data

validation. Therefore, it is necessary to find an accurate, economic and efficient approach

for FOWT design engineering practice. A new method, named as SILANN, is proposed in this

study, which utilizing Software-in-the-Loop method with artificial neural network (ANN) ap-

proach for engineering prediction. Firstly, the methodology of combing ANN with in-house

programme DARwind is introduced. Then, datasets and validation cases were selected from

the results of basin experiment and DARwind in terms of 3DOFs (surge, heave and pitch

motions). The predictions’ results show a good performance. The difference between sim-

ulation results and those of experiment can be significantly reduced by this method. This

proposed method takes advantage of the AI technology, which brings new solution for over-

coming the handicap impeding direct using of traditional basin experimental technology in

floating wind turbine design.

Keywords Basin model test, DARwind, artificial neural network, floating offshore wind

turbines, numerical simulation

47

4 Abstracts

Application of Precise Integration Method for structure dynamics in

hydroelasticity computation [46]

Zhe Sun

Dalian University of Technology, School of Naval Architecture and Ocean Engineering,

China

Abstract In the previous works, the authors have developed a mixed MPS (Moving Par-

ticle Semi-implicit) method – modal superposition model for the highly non-linear hydroe-

lasticity computation [1]. For the structure dynamic part, the rigid and flexible modes are

coupled and their mutual effects are considered. The resultant governing equations for the

structure part are highly non-linear. In order to further improve the time integration ac-

curacy, the governing equations were first reformulated into ordinary differential equation

systems, then the Precise Integration Method (PIM)[2, 3] was used to solve these equations.

The dynamics of flexible wedge was simulated by the developed numerical scheme, which

showed a better accuracy for long time simulation compared with normal schemes such as

Newmark method.

Keywords hydroelasticity

48

4.9 Offshore Structures


CFD Simulations and Model Experiments of Offshore Support Vessel

with Heavy Suspended Load in Waves [4]

Motoki Araki(1), Kazuhisa Otsubo(1), Kei Ishida(1), Kenta Hasegawa(1), Hiroshi Sato(1), Kuni-

hide Ohashi(2)

(1)National Maritime Research Institute, Ocean Engineering Department, Japan,(2)National Maritime Research Institute, Japan

Abstract Nowadays, since, subsea equipment becoming larger and heavier, risks of

the lifting/lowering operations by offshore support vessel (OSV) are also increasing and

thereby predicting coupling motions of the vessel and whirling equipment and hydrody-

namic forces acting on the suspended load in splash zone are important to prevent clash

accidents and damage on lifted subsea equipment etc. Model experiment using OSV with

heavy suspended load was conducted in Deepsea Basin in National Maritime Research Insti-

tute (NMRI). The experiments were carried out with several regular and irregular waves and

heading angles. The OSV was moored with 4 lined spring system. During the experiments,

the motions of moored OSV and suspended load were measured with visual 3D motion

capture system. Computation fluid dynamics (CFD) simulations were conducted using CFD

Solver NAGISA which was developed in NMRI to investigate the dynamics and hydrodynam-

ical aspects. Dynamic overset grid method and multibody dynamics model were applied

to reproduce the coupling motions of the vessel and suspended load. The CFD simulations

were carried out when the suspended load is in the splash zone to predict hydrodynamic

forces acting on the lifted equipment. The CFD simulation results were validated with the

model experiment comparing with motions of OSV and suspended load.

Keywords Computational fluid dynamics, Crane operation in wave, Multibody dynamics,

Offshore construction

49

4 Abstracts

Study on The Truncation Factor of Mooring System for a Ultra-deep

Water Platform [55]

Zhang Feng wei, Kuang Xiaofeng, Wu Lan, Fan Yali, Zhao Zhanhua


Abstract In this paper, the mooring system in full water depth and truncation mooring

systems in truncated water depth were designed. Truncation model test are numerical

reconstructed, then extrapolated to full depth, and compare to the full depth results, the

effect of truncation factor is analyzed, pilot study show that aiming at the target mooring

system scheme, when the truncation factor is more than 0.45, the predicted results based

on truncation model test can be reliable.

Keywords Truncation factor

Numerical Analysis of Vortex-Induced Yaw Motion of a Paired-Column

Semi-Submersible in Currents [70]

Weiwen Zhao, Decheng Wan


China

Abstract Vortex-inducedmotions (VIM) is a severe engineering problem for floating struc-

tures with slender columns. Moreover, recent studies on VIM of multi-column floating plat-

forms showed that VIM also involves prominent yaw motions. In this paper, numerical

simulations of VIM for a paired-column semi-submersible with transverse, inline and yaw

degree-of-freedom are performed by our in-house CFD solver naoe-FOAM-SJTU. To avoid

mesh distortion induced by yaw motion, a multi-block overset mesh is applied for the fluid

domain. In order to accurately predict the flow separation and wake flow, the SST-DDES

turbulence model is utilized. Vortex-induced yaw (VIY) is observed during VIM simulations.

For high current velocity cases, multi-frequency component for yaw is discovered. The vari-

ation of yaw frequencies at different reduced velocities and current headings are discussed.

Drag and lift, as well as rotational moment on each column member are analyzed.

Keywords CFD, Vortex induced yaw motions, paired column semi submersible

50


Wave-Induced Motions of Moored and Coupled Multibody Offshore

Structures [85]

Grusche Seithe, Ould El Moctar

University of Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and


Abstract In the recent past, very large floating structures (VLFS) are used to realize a

variety of large marine facilities like floating piers, bridges or logistical hubs, substituting

the traditional bottom mounted structures. In most cases VLFSs consist of a number of

individual modules that are assembled with connectors and hold in place by mooring sys-

tems. To ensure proper working and safety conditions, their hydrodynamic response in

different sea states needs to be investigated. Previous investigations relied mainly on po-

tential flow solvers which do not account for viscous and other nonlinear effects. However,

flow properties under severe conditions are highly nonlinear. To capture the physics of such

phenomena field methods are the preferred choice. The present work aims to investigate

the hydrodynamic response of such a moored and coupled multi-body VLFS in waves using

a flow code that computes multiphase unsteady incompressible flow simulations using the

Navier Stokes equations coupled with a six-degrees-of-freedom (6 DOF) multi-body solver

and mooring model. A total number of 14 simulations have been conducted for single and

multiple cuboid set-ups. The set-ups are based on the model tests performed at TU Delft.

The hydrodynamic responses were assessed and show a favourable comparison for most

cases between the computed and measured results.

Keywords CFD, VLFS, floating structures, mooring, multibody, wave induced motions

51

4 Abstracts

4.10 Offshore Wind Turbine

Coupled Response Analysis of an Offshore Articulated Wind Turbine

under Different Environmental Loads [3]

Pei Zhang, Yougang Tang

Tianjin University, China

Abstract In this paper, an offshore articulated wind turbine structure is proposed for the

water depth of 70 meters. Considering the influence of different environmental factors,

the dynamic responses of the structure are studied. Three dimensional potential flow the-

ory was used to calculate the hydrodynamic characteristics of the structure, and the blade

element momentum theory was used to calculate the aerodynamic load, the influence of

foundation motion, wave surface elevation and friction damping of articulated joint were

certainly considered. The control equation in the time domain is set up and the motion re-

sponse is solved. It is shown that the aerodynamic load has great influence on the average

response amplitude, including the average pitch angle, the rotor thrust and the tension of

articulated joint. while the wave load is related to the variation of amplitude. The struc-

ture will produce a large coupling low-frequency response in the low-frequency range with

wave and wind. Especially, under the action of turbulent wind, the coupling effect increases

sharply.

Keywords Hydrodynamic performance of offshore systems

52


Experimental and Numerical Study for Weathervane and Stability

Performance of Single-Point-Moored FOWTs Under Wind-Current

Coexisting Field [9]

Kazuki Hashimoto(1), Sharath Srinivasamurthy(1), Kazuhiro Iijima(2), Yasunori Nihei(1)

(1)Osaka Prefecture University, Marine System Engineering, Japan,(2)Osaka University, Naval Architecture and Ocean Engineering, Japan

Abstract Recently, Floating Offshore Wind Turbines (FOWTs) are attracting a great deal

of attention as offshore renewable energy source in terms of its energy efficiency and poten-

tial. Wind turbines normally weathervane using the yaw control system. However, the yaw

control system is found to be one of the major reasons for the failure of wind turbines. Es-

pecially, in the case of Floating Offshore wind turbines, when the yaw control system breaks

down, it becomes all the more difficult to repair it on the sea because of the high altitude

and waves. Also if the failure is severe, the wind turbine need to be towed back to docks

increasing maintenance costs. As one of the solution of this problem, Single Point Mooring

(SPM) system is proposed. FOWTs moored to SPM system can rotate around the mooring

point and follow the wind direction without yaw control system. In this study, the weath-

ervane and stability performance of FOWTs moored to SPM system in the wind and current

coexisting field is considered through a series of experiments and numerically simulating

time-series history. First, we designed and manufactured 1/200 scale models of two types

FOWTs, a semi-submersible and spar, based on Froude’s scaling law. The scaled models

are experimented in a circulating water tank at Osaka Prefecture University, Osaka, Japan.

It was found out that the weathervane performance of both the FOWTs types was accept-

able in rated wind and slow speed current condition. However, in the rated wind and high

speed current condition, the weathervane performance especially of the semi-submersible

type was not acceptable and instability oscillation of spar type was observed. In addition,

a numerical simulation program was developed with an assumption of modeling the SPM-

FOWTs as a double pendulum. In this time history program, the effect of the bearing on the

mooring buoy is considered for clear understanding. The result of the program is discussed

and compared to the results of the experiments.

Keywords Hydrodynamics of renewable marine energy and ocean resources

53

4 Abstracts

Craneless Upending of Large Offshore Monopiles Using A Specialised

Floater [18]

Pascal Voges(1), Axel Nernheim(2), Marc Seidel(2), Christian Schulz(1), Moustafa Abdel-Maksoud(1)

(1)Hamburg University of Technology, Fluid Dynamics and Ship Theory, Germany,(2)Siemens Gamesa Renewable Energy, Germany

Abstract The paper presents the concept of a Floater for Upending Piles (FlUP), which

can be considered as an efficient approach for installation of very large offshore monopiles

for the offshore-wind industry. This principle is embedded into a concept aiming to decou-

ple the monopile installation steps of upending and pile driving. The idea of the FlUP is to

shift the pile from horizontal to vertical position with a self-ballasting floater and utilise a

small crane-vessel docking on the floater for pile-driving operations afterwards. The key

component of this concept is the FlUP, which is able to upend itself carrying the monopile

by shifting ballast water using pumps. A feasibility study of this approach, including a pre-

liminary design of a floater and corresponding design-relevant calculations is presented.

The study includes examinations of hydrostatic stability as well as seakeeping behaviour

computations to evaluate the limiting sea states for installation in an offshore environment.

Afterwards the general feasibility of this concept regarding hydrostatic and seakeeping as-

pects is demonstrated.

Keywords Craneless Upending, Foundation Installation, InstallationMethod, LargeMonopile,

Offshore Wind, Upending Floater

54


Numerical Analysis of A Floating Horizontal Axis Tidal Current Turbine

with Sway Motion [30]

Chen Zeng, Moustafa Abdel-Maksoud


Abstract Increasing the rotational speed of a turbine rotor leads to a reduction of the

stream velocity passing through the rotor. By diverging the upstream flow, the slowed wake

reduces the fluid mass flowing through the rotor, and thus, the power output. The present

study aims to determine if and by which extent a sway motion, by deviating the turbine

rotor from the following delayed wake, is able to improve the power output of a turbine.

A low-order panel method, namely panMARE, is applied, and the DOE Reference Model 1

turbine is used as the test object. First, a series of open-water simulations is carried out

and compared with the corresponding RANS results to verify the numerical setup. Then, the

hydrodynamic behaviour of a turbine swaying sinusoidally with two different time periods

are simulated. The results indicate that the sway motion does help to improve the power

harness of the turbine and the improvement increases with the increase of the maximum

sway velocity as well as the tip speed ratio of the turbine rotor. Some other characteristics

of the turbine in sway motions are also investigated by the subsequent data analysis.

Keywords Betz limit, Panel method, Sway motion, Tidal current turbine, Wake

Dynamic response of a novel reduced draft Spar-type FOWT with

anti-motion damping structure [31]

Pei Zhang, Yan Li, Yougang Tang

Tianjin University, China

Abstract With regard to the offshore areas in China, the water depth is limited so that the

traditional Spar-type FOWTs are not suitable to be installed in these areas. In this work, we

proposed a novel reduced draft Spar-type FOWT with anti-motion damping structure. Sim-

ulations are conducted in both frequency and time domain to investigate the dynamic re-

sponse of the FOWT in different scenarios. Towards this end, a coupled aero-hydro-mooring

numerical model is developed. The methodology includes a blade-element-momentum

model for aerodynamics, a nonlinear model for hydrodynamics, a nonlinear restoring model

of SPAR buoy, and a nonlinear catenary model for mooring cables. The motions of platform,

the tensions in the mooring lines and the power generation performance are documented in

different cases. The dynamic performance is also compared with the classic Spar-type wind

turbine. According to the results, it shows that the reduced draft Spar-type FOWT is effective

to support the 5MW baseline offshore wind turbine in the limited water-depth area.

Keywords FOWT, aerodynamics, dynamic response, reduced draft

55

4 Abstracts

LES Study of Wind Turbine Wake Meandering in the Atmospheric

Boundary Layer [69]

Xu Ning, Decheng Wan


China

Abstract Actuator line model and CFD technique are introduced in the present work to

learn the evolution of a wind turbine wake especially the wake meandering phenomenon

under the atmospheric inflow condition. The simulation is implemented by applying the

actuator line model to the ABL-LES solver, which is developed based on the CFD toolbox

OpenFOAM by the researchers at the National Renewable Energy Laboratory (NREL). The

time averaged velocity contours show that the shear layer starting behind the blade tip

and root under turbulent inflow develops faster than that under uniform inflow, but under

the strong mixing effect of atmospheric boundary flow the velocity inside the wake is redis-

tributed immediately behind the rotor and the recovery process is much more accelerated

than other cases. Temporal filter is used to smear out the high frequent turbulence while

conserve the large scale flow structure. From the results of filtered flow field, it is found

that uniform inflow and homogenous turbulent inflow cannot induce wake meandering and

the large scale movement of wind turbine wake is only observed under atmospheric flow

condition. Furthermore, a dominant wave length of and a similar meandering frequency of

in different positions downstream are obtained through further quantitative analysis.

Keywords Atmospheric boundary layer, LES, Wake meandering

56

4.11 Wave Dynamics

4.11 Wave Dynamics

A Modified Model for Waves Generated by a Moving Body in a Stratified

Fluid with Free Surface [6]

Yuhang Li, Ke Chen, Yunxiang You


China

Abstract The model proposed by Milder and further developed by Robey and You is ca-

pable of expressing the internal wave generated by a moving sphere or cylindrical body

a satisfied fluid. Unfortunately, this model cannot describe the surface wave because of

the rigid lid assumption. In this paper, a modified model is established with linearized gov-

erning equations and the free surface condition. This modified model can describe both

the internal and surface wave excited by a submerged cylindrical body, and is feasible to

arbitrary density profiles. In the investigation, the eigenvalue parameter is first obtained

by solving the eigenvalue problem under the boundary condition through Thomson-Haskell

method. The eigenvalue parameter is then employed to construct the Green function. The

vertical displacement induced by the moving objects is obtained after solving the Green

function through Fourier transform in finite or infinite water depth. The results are com-

pared to experimental results and classical theory, respectively. The comparisons show

good agreement. The results also show that the waveform consists of multiple wave modes

from mode-0 to mode-n. It is also found that mode 0 is associated to the surface wave and

the other modes are related to the internal waves.

Keywords free surface, internal wave, stratified fluid, theoretical model

57

4 Abstracts

Damping of Non-Linear and Irregular Long-Crested Free-Surface Waves

Using Forcing Zones [17]

Robinson Perić, Moustafa Abdel-Maksoud


Abstract In flow simulations, it is typically desired to choose the solution domain as

small as possible to reduce the computational effort. Therefore, when simulating free-

surface wave propagation, undesired wave reflections at the domain boundaries must be

minimized.

Forcing zones (such as absorbing layers, damping zones, sponge layers, relaxation zones,

etc.) can be used to reduce such undesired wave reflections. They introduce source terms

in one or several of the governing equations in a zone adjacent to the corresponding domain

boundaries, with the intention of gradually forcing the solution within the zone towards some

reference solution. The problem with forcing zones is to find the optimum values for their

case-dependent parameters.

Perić and Abdel-Maksoud (2018) presented a theory which predicts the reflection coeffi-

cients and the flow within forcing zones in finite-volume-based flow simulations with free-

surface waves.

In the present work, finite-volume-based flow simulations are performed with long-crested

wave trains traveling towards a domain boundary, to which a forcing zone is attached

to damp the waves. Simulations are performed for regular deep-water waves with up to

roughly 85% of the maximum wave steepness, and for irregular shallow-water waves, with

different parameters of the forcing zone. The resulting reflection coefficients are compared

to theory predictions.

When the forcing zone was tuned using the developed theory, the simulation results for

the reflection coefficient were in most cases smaller or nearly equal to those predicted by

theory, but never more than 2.1% larger. Thus the theory is recommended also for tuning

forcing zones with non-linear and irregular free-surface waves.

Keywords flow simulation, forcing zones, free surface waves, irregular waves, nonlinear

waves, wave damping

58

4.11 Wave Dynamics

Diffraction of Wavefront around Cylinders [43]

Ruipeng Li, Xiaobo Chen, Wenyang Duan

Harbin Engineering University, College of Shipbuilding Engineering, China

Abstract The diffraction of transient waves around an infinite cylinder vertically fixed in

deepwater is considered. The velocity potential and corresponding normal derivatives on

the cylinder surface are expanded by the Laguerre function in vertical direction and Fourier

series along the circumference. Green’s Theorem is applied in the domain external to the

cylinder, to obtain the so-called Dirichlet-to-Neumann (DtN) operator, which represents the

relationship between series expansion coefficients related to the velocity potential and its

normal derivative on the cylinder. Transient waves diffracted from any kind of incoming

waves can then be obtained by applying the above DtN operator. The boundary integral

equation (BIE) established in the fluid domain is a three-folds integral, twowith respect to the

cylinder surface and one with respect to time, and the time-domain Green function itself is a

single one. In the scheme of Galerkin collocation, to obtain the DtN operator, the boundary

integral equation is multiplied by a base function on both sides and integrated over the

cylinder surface. A new boundary integral equation connecting the expansion coefficients

related with velocity potential and normal derivative is obtained. Although all elements

in the coefficients matrix are multi-folds integrals in form, they can be reduced to single

ones with respect to wavenumber by using orthogonal properties of Laguerre functions and

Fourier series, except for the convolution integral which can be expressed by a summation.

Unlike in classical work where steady-state plane progressive waves are involved, transient

waves with wavefronts, which are generated by a wavemaker, are selected as the incoming

waves in present study. Wavefront can be observed in real sea, physical wave tank and

numerical simulations. A study on transient waves with wavefronts is of importance to

understand better the wave diffraction by cylinders. Results from the above method are

compared with those from an existing time-domain analyzing method.

Keywords Fourier Laguerre series expansion, Wave diffraction, time domain Green func-

tion, wavefront

59

4 Abstracts

Quantitative Evaluation of Temporal Variation for the Short-Crested

Irregular Wave Generated in Experimental Wave Basin [60]

Daichi Ota, Takako Kuroda, Hidetaka Houtani

National Maritime Research Institute, Japan

Abstract In a model test aimed at investigating statistically the ship response in an ac-

tual sea condition, it is needed that the short-crested irregular waves are generated for a

long duration. The characteristics of the wave field should be kept unchanged in time. In

this study, the authors have investigated the temporal variation of a short-crested irregular

wave field in an experimental wave basin. An experiment of wave generation was carried

out in the Actual Sea Model Basin (ASMB) of National Maritime Research Institute in Japan.

Wave elevations were measured with six wave gauges to estimate the directional spectrum.

In order to evaluate quantitatively the temporal variation of the wave field, the authors in-

troduced the indicators of the wave spectrum shape such as significant wave height, mean

wave period, mean wave direction, and mean spreading angle. The authors evaluated the

temporal variation of the experimental wave field generated in the ASMB by using these

indicators. In addition, the variation of the proposed indicators of the wave spectrum shape

due to the development of the reflected wave along with wave generation time was inves-

tigated by numerical simulation. The introduction of these wave parameters allowed us to

quantify the temporal variation of wave fields.

Keywords directional spectrum, irregular waves, wave basin

60

4.11 Wave Dynamics

RANS Model for Bow Wave Breaking of a KRISO Container Ship under

Different Speeds [72]

Anzheng Yu, Decheng Wan


China

Abstract RANS model combined with VOF method is used to simulate the bow wave

breaking of KCS model in the present work. Numerical simulations under seven Froude

numbers are conducted in our inhouse CFD solver naoe-FOAM-SJTU. The results of total re-

sistance coefficient and wave pattern at Fr=0.26 are used for CFD validation. The results

of resistance coefficients and wave surface on ship hull under different Froude numbers are

analysed, the overall results show that present numerical methods can deal with the com-

plex flow around ship model. Comparisons of bow wave between model test and CFD at

Fr=0.26, 0.35, 0.425 are given, the vorticities induced by bow wave breaking is also anal-

ysed. In order to figure out the mechanism of bow wave breaking, detail analysis of wave

cuts is provided at Fr=0.35, both plunging and spilling wave-breaking are found as well as

air-entertainment and splash. Present RANS model can accurately capture the overturn-

ing of bow wave but cannot deal with the unsteady capillary wave which is found in model

test.

Keywords Bow Wave Breaking, KRISO Container Ship, RANS Model

61

4 Abstracts

4.12 Wave Induced Motions and Loads

CFD Analysis of Ship Oblique Towing in Waves [11]

Zhang Zhu, Jae-Hoon Lee, Yonghwan Kim


South Korea

Abstract Ship oblique towing test is a fundamental component of the Planar Motion

Mechanism (PMM) test which is a series of captive model tests for obtaining maneuver-

ing derivatives. Those maneuvering derivatives play very critical roles in the mathematical

model which is built for predicting ship maneuvering performance. Typical tests and predic-

tions are conducted based on calm water condition, but in fact a case with incident wave is

more close to real ship sailing environment and it can induce very different ship resistance

and motion response. Present paper considers the oblique towing test in waves, observ-

ing the wave effect on ship response as well as maneuvering derivatives. Since the test

involves significant nonlinearity and strong viscous effect, present analysis uses a commer-

cial Computational Fluid Dynamics (CFD) program. The oblique towing test selects scaled

S-175 hull as test model, and towing condition varies in oblique towing angle and incident

wavelength.

Keywords Computational fluid dynamics, maneuverability, propulsion, resistance, sea-

keeping

62


Comparative Study on Different CFD Solvers for Analysis of Ship Added

Resistance [14]

Byung-Soo Kim(1), Kyung-Kyu Yang(2), Zhang Zhu(1), Yonghwan Kim(1)

(1)Seoul National University, Department of Naval Architecture and Ocean Engineering,

South Korea,(2)Korea Research Institute of Ships & Ocean Engineering, South Korea

Abstract This study deals with motion responses and the added resistance of the ship

in waves using computational fluid dynamics (CFD). In this study, motion response and

the added resistance of the modified blunt Wigley are investigated using two types of CFD

program: SNU-MHL-CFD (Seoul National University Marine Hydrodynamics Laboratory CFD)

and OpenFOAM. SNU-MHL-CFD is Euler equation solver which is an in-house code based on

a Cartesian-grid and immersed boundary method. OpenFOAM is Reynolds-Averaged Navier-

Stokes (RANS) equation solvers which is an open source library. Before solving the ship mo-

tion in waves, hydrodynamic coefficients are calculated by forced heave and pitch motions

and wave excitation forces/moments are computed from wave diffraction problem without

any hull motion. Three types of solvers are used: two previously mentioned solvers and

additionally commercial software, Star-CCM+. These results are validated with the experi-

mental data. Finally, ship motion responses and added resistance in waves are compared

with available experimental data and their computational costs are compared.

Keywords Computational fluid dynamics

63

4 Abstracts

Numerical Study on Steady Wave Drift Forces of an Obliquely Moving

Ship [20]

Wei Zhang(1), Ould El Moctar(2)

(1)China University of Petroleum (East China), China,(2)University of Duisburg-Essen, Institute of Ship Technology, Ocean Engineering and


Abstract This paper considers numerical computation of the steady wave drift forces

acting on an obliquely moving ship. The traditional forward speed seakeeping problem was

extended to consider the ship with a drift angle. A computer code was developed based

on a time domain Rankine panel method. Once the velocity potential around the hull was

determined, the first order wave induced motions were calculated and then the second

order wave drift forces were evaluated using a near field method. Based on the developed

code, the longitudinal and transverse steady wave drift force, as well as the steady yaw

moment were computed for a container ship in head and beam waves. The effects of the

drift angle on the steady wave drift forces were included and discussed. The numerical

results were compared with the published experimental measurements, which shows fairly

good agreement.

Keywords Drift angle, Obliquelymoving ship, Rankine panel method, Second order wave

effect, Wave drift force

64


Experimental Study on Hydrodynamic Forces Acting on Ship Hull and

Rudder behind the Propeller in Regular Waves [33]

Van Minh Nguyen(1), Seo Ju Won(1), Yeon-Gyu Kim(2), Hyeon Kyu Yoon(1)

(1)Changwon National University, Korea, Department of Eco-friendly Offshore Plant FEED

Engineering, South Korea,(2)Korea Research Institute of Ships & Ocean Engineering, South Korea

Abstract In recent years, intensive efforts are being concerned toward the predicting

ship maneuvering performance in waves. Since ship maneuverability highly influenced by

the wave on the water surface, enhancement of ship maneuverability at the ship design

state is an important method. In this paper, the model test is performed for investigating

the impact of wavelength and wave direction on the hydrodynamic force of a ship hull and

rudder. The number of propeller revolution is determined for themodel speed corresponding

to full-scale service speed in calm water is kept constant during the test. The hydrodynamic

force of rudder and ship hull have measured in calm water and in regular waves. In order

to confirm the experimental result, the added resistance in wave in head sea is compared

with results from other institutes. The added resistance in wave in head sea shows fair

agreement with experimental results of different institutes. The changing of hydrodynamic

forces of a ship and rudder in various wavelengths is discussed in various wave directions

and rudder angle. Hydrodynamic forces acting on the ship hull and rudder behind propeller

are compared with one without propeller.

Keywords hydrodynamic forces

65

4 Abstracts

Quick Evaluation of Seakeeping Performance for Ship Hull Form

Optimization [67]

Jinkai Wang, Decheng Wan


China

Abstract At present, most of the ship hull form optimization designs aim to reduce ship

resistance. As the ship speed requirements continue to increase, the ship seakeeping per-

formance is also particularly important. A fast and sensitive seakeeping evaluation program

is the basis for ship hull form optimization with the aim of seakeeping performance. In this

study, based on the strip theory, Tasai atlas of Lewis section is interpolated to calculate the

damping coefficient and additional mass of the two-dimensional slice. Then, based on the

Salvesen method, ship heave and pitch coupled motion equations in the wave are used to

solve the pitch and heave motion of the ship in different wave directions. Finally, Wigley

ship is calculated by the program above, and the evaluation results are compared with the

experimental values. The results show that this method can quickly and accurately evaluate

the heave and pitch motions of ships, which can greatly shorten the optimization time.

Keywords Quick Evaluation, Ship Hull Form Optimization, seakeeping

66


Experimental and Numerical Evaluation of the Added Wave Resistance

for an Ultra Large Container Ship in Shallow Water. [75]

Luca Donatini(1), Manases Tello Ruiz(1), Guillaume Delefortrie(2), José Villagómez(2), Evert

Lataire(1), Marc Vantorre(1)


Abstract In this paper, the added wave resistance of an Ultra Large Container Ship

(ULCS) in shallow water is investigated both experimentally and numerically. The experi-

mental results come from a series of tests performed in the Towing Tank for Manoeuvres

in Confined Water (co-operation Flanders Hydraulics Research and Ghent University) in

Antwerp (Belgium) in 2016. Tests were executed for head and following waves, with two

wave amplitudes, and using two different beam frames to attach the ship to the towing

tank’s carriage. One of the frames restrained the heave and pitch motions while the other

one allowed the free motion of both. The results of experiments outline the proportional-

ity of added resistance on the square of the wave amplitude in shallow water conditions.

Moreover, the expected behaviour of added resistance at different wave lengths can be ob-

served: in long waves, the added resistance is tightly related to the ship motions, while in

short waves it achieves an asymptotic trend. In following waves, a peculiar phenomenon is

noticed: at moderate forward speeds a positive added resistance of substantial magnitude

is measured for a specific, speed dependent interval of wave lengths. This phenomenon is

investigated and preliminary ascribed to the interaction between the incident wave field and

the return current originated by the motion of the ship in shallow water. Numerical simula-

tions are performed with two potential codes: one based on strip theory and one 3D panel

code. The 3D panel code performs better than the strip theory code. An in-depth analysis of

the added resistance and vertical motions is performed, and the discrepancies of simulated

added resistance with respect to experiments are mainly ascribed to the inaccuracies of

numerical codes in the calculation of heave and pitch RAOs and phases.

Keywords Added resistance, container ship, experimental, numerical, shallow water

67

4 Abstracts

Analysis of the Second Order Wave Forces Acted on a Floating Pontoon

[79]

Yuji Miao(1), Xujun Chen(1), Haipeng Shen(1), Xiao Wei(1), Kai Lu(1), Guanghuai Wu(2)

(1)Army Engineering University of PLA, College of Field Engineering, China,(2)Nanjing Guangbo Engineering Technology co. LTD, China

Abstract In order to analyse the second order wave force on a abnormity floating pon-

toon and the influence of dimensions of the appended pontoons and water depth on the

second order wave force of the structure, the second order hydroelasticity theory of ships

was used to calculate the second order wave force. The second order wave force include

the difference-frequency and sum-frequency fluid forces. The first order wave potentials

and responses are sure to make the major contributions to the second order hydrodynamic

actions, so the first order motions of the structure were calculated and verified by compar-

ison with the experimental results. The second order wave force of the abnormity floating

pontoon was calculated and compared in the different water depth. The results showed

that the water depth has significant influence on the second order wave force on the pon-

toon. And the results also showed that the mean drift force was only sensitive to the wave

direction in the medium and high wave frequency domain.

Keywords hydroelasticity theory, second order wave forces, water depth, wave poten-

tials

68

5 Notes

5 Notes

69

the11th internationalworkshopon shipandmarinehydrodynamics ... · 3program monday,september23,2019...

Documents