previous sailing yachts seakeeping investigation in...
Post on 09-Sep-2018
226 Views
Preview:
TRANSCRIPT
Previous sailing yachts seakeeping
investigation in view of a new set of rules
Adrien Combourieu
Academic Supervisor: Prof. Dario Boote, UNIGE
Industrial Supervisor: Flavio Faloci, RINA
External Reviewer: Prof. Leonard Domnisoru, UGAL
La Spezia, 25th of January 2013
Contents
Introduction
Method for quick pitch RAO estimation
State-of-the-art method for motion in irregular sea prevision
Conclusions
Erasmus Master Course in Advanced Ship Design
3
25/01/13
Introduction - Objectives
Yacht dismasting investigation
Seakeeping => inertial loads
Acceleration mainly due to pitch
Hydrostar: potential seakeeping code in frequency domain (BV)
Classification society => quick method
Key parameters?
25/01/13 Erasmus Master Course in Advanced Ship Design
4
Introduction – Database
25/01/13 Erasmus Master Course in Advanced Ship Design
5
7 modern sailing boat hulls
name
LOA (m)
Lwl (m)
B (m)
T canoe (m)
Displacement (kg)
ballast mass (kg)
kyy (m)
SW 31.3 30.4 6.8 1.08 83856 18700 8.70
swan 90 26.8 24.9 6.6 0.95 56726 18400 7.08
oyster 82 24.8 20.9 6.3 1.29 61085 20243 6.33
swan 66 20.3 17.8 5.4 0.90 31030 9400 5.37
ref2 14.5 12.8 4.3 0.66 12877 4507 3.63
AME004 11.3 10.3 3.1 0.44 5381 1883 2.79
J80 8.0 7.0 2.5 0.34 1825 635 2.11
25/01/13 Erasmus Master Course in Advanced Ship Design
6
Waterline length Lwl
Method for quick pitch RAO estimation
Method for quick pitch RAO estimation
RAO: 2 representations
25/01/13 Erasmus Master Course in Advanced Ship Design
7
0 10 20 30 40 50 60 70 80 900
0.2
0.4
0.6
0.8
1
amplitude pitch.rao
lambda (m)
pitch.r
ao(r
ad/r
ad)
180°
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
2
4
6
8
10
12
14amplitude pitch.rao
f (Hz)
pitch.r
ao
(
deg/m )
180°
L1
L0
f0 f1 fres
pmax
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
8
λ>L1
λ<L0
L1≈2*Lwl
L0≈0.5*Lwl
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
9
Regression on 7 hulls
λres = 1.2485Lwl + 0.0331
R² = 0.9909
0
5
10
15
20
25
30
35
40
45
0,00 10,00 20,00 30,00 40,00
λre
s (m
)
Lwl (m)
λres
Linéaire (λres)
fres = 1.118/sqrt(Lwl)
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
10
Regression on 7 hulls
fres = 1.118/sqrt(Lwl)
pmax = 39.985e-0.06Lwl
y = 39.985e-0.06x
R² = 0.9728 0,00
5,00
10,00
15,00
20,00
25,00
30,00
35,00
0,00 10,00 20,00 30,00 40,00
ma
xim
um
pit
ch a
mp
litu
de
(°)
waterline length (m)
pitch max
Expon. (pitch max)
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
11
Regression on 7 hulls
fres = 1.118/sqrt(Lwl)
pmax = 39.985e-0.06Lwl
y = 0,4287x + 0,6819
R² = 0,9883
0
2
4
6
8
10
12
14
16
0,00 10,00 20,00 30,00 40,00
λ0
(m
)
Lwl (m)
λ0(5%)
Linéaire (λ0(5%))
L0 = 0.429Lwl
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
12
Regression on 7 hulls
fres = 1.118/sqrt(Lwl)
pmax = 39.985e-0.06Lwl
y = 2,4512x - 6,5245
R² = 0,8352 0
10
20
30
40
50
60
70
80
90
0,00 10,00 20,00 30,00 40,00
λ1
(m
)
Lwl (m)
λ1 (95%)
Linéaire (λ1 (95%))
L0 = 0.429Lwl
L1 = 2.5Lwl
Method for quick pitch RAO estimation
25/01/13 Erasmus Master Course in Advanced Ship Design
13
Results on Kiboko
0 0.1 0.2 0.3 0.4 0.5 0.60
1
2
3
4
5
6
7
8
amplitude pitch.rao
f (Hz)
pitch.r
ao
(
deg/m )
180°
Pitch in irregular sea
25/01/13 Erasmus Master Course in Advanced Ship Design
14
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
2
4
6
8
10
12
14amplitude pitch.rao
f (Hz)
pitch.r
ao
(
deg/m )
180°
X
2
Frequency domain
Pitch in irregular sea
25/01/13 Erasmus Master Course in Advanced Ship Design
15
Time domain
0 5 10 15 20 25 30 35-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0.25wave time serie
t (s)
Wave a
mplit
ude (
m)
0 5 10 15 20 25 30 35
-3
-2
-1
0
1
2
3
pitch.rao time serie
t (s)
deg/m
*m
Pitch in irregular sea
25/01/13 Erasmus Master Course in Advanced Ship Design
16
Comparison with experimental results for J80
•In pure front waves
•speed = 5 knots.
•Hs=0.3m
•Tp = 2.251s
•ɣ=3.3 (closed basin)
•No heel angle
Augier, B., Bot, P., Hauville, F., Durand, M., (2012), “Experimental validation of unsteady models for fluid
structure interaction: Application to yacht sails and rigs”. Journal of Wind Engineering and Industrial
Aerodynamics, 101 (2012), pp 53–66
Experimental
Numerical
Pitch in irregular sea
25/01/13 Erasmus Master Course in Advanced Ship Design
17
Results for kiboko in irregular head sea without speed
Numerical
Empirical
Conclusion
25/01/13 Erasmus Master Course in Advanced Ship Design
18
Critical parameters: Lwl, kyy, V, stern (bow) shape, heading
Simplified method for head sea without forward speed using only
Lwl. To be improved taking into account more parameters.
Regression on bigger database
Method for pitch prediction in function of wind speed to be
compared with experimental results
Thank you for your attention
Questions ?
25/01/13 Erasmus Master Course in Advanced Ship Design
19
top related