The application of CFD at Heerema Marine Contractors STAR Global Conference 2012 - Noordwijk

Presented by: Harald Ottens Date: 21 March 2012

2

Heerema Marine Contractors (www.heerema.com)

Marine Contractor in the offshore Oil and Gas Industry

HMC transports, installs and removes all types of offshore facilities

Focusing on complex projects, from conceptual design to completion

Operating 3 of the 4 largest construction vessels in the world

New vessel: DCV Aegir (2013)

3

CFD applications within HMC

Current Affairs JIP - Current loads - VIM

Suction pile lowering - Added mass - Damping coefficients

H-851 - Tow resistance /

Shape optimization - Viscous damping

Current Loads - SSCV - Aegir

Thrust efficiency

4

Towing resistance: H-851 Modification

5

Current Applications – H-851 Modification

Float-over Topsides installation in Woodside Australia Modification of H-851

6

Current Applications – H-851 Modification

10%

3%

Mid-bow shape - Final shape concepts - CFD computations to determine which shape has lower resistance

Results - More than 10% tow-resistance reduction - Another 3% tow-resistance reduction by applying wing-tanks

7

Lowering Dynamics – Deep water installation

Resonance effects on dynamic behavior

- Load fluctuations in hoisting wires - Overload in cranes - Slack in wires

Maximum set-down velocity

3,000m

8

CFD Analysis– Morphing Mesh

Morphing mesh used to include effect of bottom

9/20

Results - Morphing mesh, h/d = 0.40

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11

1.2

1.4

1.6

1.8

2

Ca [-]

Ca-mt

Mean-mt

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.05

0.1

0.15

0.2

Be [-]

KC [-]

Be-mt

Trend-mt

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 11

1.2

1.4

1.6

1.8

2

Ca-cfd = 1.57 [-], Ca-mt = 1.49 [-]

Ca [-]

Ca-mt

Mean-mt

Ca-cfd

Mean-cfd

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.05

0.1

0.15

0.2

B1-cfd = 0.043 [-], B2-cfd = 4.63 [-], B1-mt = 0.072 [-], B2-mt = 3.03 [-]

Be [-]

KC [-]

Be-mt

Trend-mt

Be-cfd

Trend-cfd

Added mass of ballast module

10

Thrust efficiency – Validation at model scale

Validation of thruster efficiency using CFD with available model test data (@ MARIN, The Netherlands)

- Open water thruster - Thruster-hull interaction with 8 active thrusters

11

Open water thruster – Force definitions

Tunit: 6 component frame Tprop & Qprop: on shaft Tnozzle: on support

12

Open water thruster - Moving Reference Frame

Disadvantage MRF: # Cells

Option: Momentum source

13

Loss of accurate thrust component using AMS

Tnozzle AMS = 60% of Tnozzle MRF During model tests all force components are measured MRF is used

14

Thruster wake development below SSCV

15

Pressure distribution – 8 thrusters active

16

17

Thrust efficiency, 4kn current

OW

CURYTHYCURXTHX

THT

FFFFC

2,,

2,,

Validation on full scale: Thialf

18

Thialf – data sheet

Largest Deepwater Construction Vessel Tandem lift capacity 14,200t (15,600 short tons)

Dimensions:

- Length overall 201.6m (661 ft) - Length of vessel 165.3m (542 ft) - Width 88.4m (290 ft) - Depth to workdeck 49.5m (162 ft) - Draught 11.8 – 31.6m

(43 – 104 ft)

Class III Dynamic Positioning System - 6 x 5,500 kW – 360 azimuth (Wärtsilä)

More info: www.heerema.com

19

Test cases

20

All thrusters azimuth 0° P1 & S1 P2 & S2 P3 & S3 P1, P2, S1 & S2 P1, P3, S1 & S3 P2, P3, S2 & S3

Top view

1.00

0.47 0.43

0.62

0.71

0.85

0.77

1.00

0.53

0.45

0.63 0.66

0.71 0.68

All thrusters P1 & S1 P2 & S2 P3 & S3 P12 & S12 P13 & S13 P23 & S23

Case 4 Case 5 Case 6 Case 7 Case 8 Case 9 Case 10

Thialf test data vs. CFD: Effect Thrust Settings Relative speed (wrt Case 4)

Test data CFD results

Bar plots ratio’s

21

Same trends!

Summary

22

HMC has used CFD (STAR-CCM+) successfully for different subjects - Towing resistance / current loads - Added mass & Damping coefficients - Thrust efficiency

Validation on model scale and on full scale!