Abstract

The oscillating water column (OWC) responses within forward, central, and aft located moonpools for a fixed rectangular vessel are studied numerically under regular head wave conditions using Reynolds-averaged Navier–Stokes-based computational fluid dynamics calculations. The free surface elevation of the confined water inside the moonpool for the piston mode frequencies is studied independently for the forward, central, and aft moonpools, showing a strong dependence on location, draft, and incident wave frequency. The relative response is largely magnified for wave frequencies around the resonant range. It is observed that the free surface response amplitude is significantly higher in the forward moonpool location, and the results are in well comparison with experiments performed in the towing tank. The variation of dynamic pressure and its influence on the moonpool responses is investigated to understand the position-specific fluctuations, which showed the presence of harmonics. The phase difference between the water column oscillations within the moonpool and the propagating wave in the domain depends on its position. Finally, the effect of the moonpool in modifying the pressure field is studied by comparison with a vessel without moonpool for a common incident wave frequency.

References

1.
Fakuda
,
K.
,
1977
, “
Behaviour of Water in Vertical Well With Bottom Opening of Ship, and Its Effects on Ship-Motion
,”
J. Soc. Nav. Archit. Jpn.
,
1977
(
141
), pp.
107
122
.
2.
Aalbers
,
A. B.
,
1984
, “
The Water Motions in a Moonpool
,”
Ocean Eng.
,
11
(
6
), pp.
557
579
.
3.
Gaillarde
,
G.
, and
Cotteleer
,
A.
,
2004
,
Water Motion in Moonpools Empirical and Theoretical Approach
,
Association Technique Maritime of Aeronautique, Paris
.
4.
Bull
,
D.
,
2015
, “
An Improved Understanding of the Natural Resonances of Moonpools Contained Within Floating Rigid-Bodies: Theory and Application to Oscillating Water Column Devices
,”
Ocean Eng.
,
108
, pp.
799
812
.
5.
Xu
,
X.
,
Zhang
,
X.
,
Chu
,
B.
, and
Huang
,
H.
,
2020
, “
On Natural Frequencies of Three-Dimensional Moonpool of Vessels in the Fixed and Free-Floating Conditions
,”
Ocean Eng.
,
195
, p.
106656
.
6.
Kristiansen
,
T.
, and
Faltinsen
,
O. M.
,
2008
, “
Application of a Vortex Tracking Method to the Piston-Like Behaviour in a Semi-Entrained Vertical gap
,”
Appl. Ocean Res.
,
30
(
1
), pp.
1
16
.
7.
Feng
,
X.
,
Bai
,
W.
,
Chen
,
X. B.
,
Qian
,
L.
, and
Ma
,
Z. H.
,
2017
, “
Numerical Investigation of Viscous Effects on the Gap Resonance Between Side-by-Side Barges
,”
Ocean Eng.
,
145
, pp.
44
58
.
8.
Sivabalan
,
P.
, and
Surendran
,
S.
,
2017
, “
Numerical and Experimental Study on Varying Cross-Section of Moonpool for a Drill Ship
,”
Sh. Offshore Struct.
,
12
(
6
), pp.
885
892
.
9.
Yadav
,
A.
,
Subramanian
,
V. A.
, and
Ananthakrishnan
,
P.
,
2021
, “
Numerical and Experimental Investigation of the Effect of Moonpool Positioning on the Hydrodynamics of Floating Drilling Production Storage and Offloading Vessel
,”
Sh. Offshore Struct.
,
17
(
5
), pp.
973
991
.
10.
Jiang
,
S. C.
,
Bai
,
W.
, and
Yan
,
B.
,
2021
, “
Higher-Order Harmonic Induced Wave Resonance for Two Side-by-Side Boxes in Close Proximity
,”
Phys. Fluids
,
33
(
10
), p.
102113
.
11.
Molin
,
B.
,
Zhang
,
X.
,
Huang
,
H.
, and
Remy
,
F.
,
2018
, “
On Natural Modes in Moonpools and Gaps in Finite Depth
,”
J. Fluid Mech.
,
840
, pp.
530
554
.
12.
Garad
,
S.
,
Bhattacharyya
,
A.
, and
Datta
,
R.
,
2019
, “
Water Column Response Within a Barge Having Bottom Openings
,”
Royal Institution of Naval Architects (RINA)—6th International Conference on Ship and Offshore Technology
,
Kharagpur, India
, Nov. 7–8, pp.
154
161
.
13.
Garad
,
S.
,
Bhattacharyya
,
A.
, and
Datta
,
R.
,
2021
, “
Oscillating Water Column Behaviour at Forward, Central, and Aft Locations Within a Fixed Vessel
,”
Ocean Eng.
,
236
, p.
109251
.
14.
Garad
,
S.
,
Bhattacharyya
,
A.
, and
Datta
,
R.
,
2022
, “
Resonant Oscillations Within Multiple Moonpools for a Fixed Rectangular Vessel
,”
J. Ship Res.
, pp.
1
11
.
15.
Elhanafi
,
A.
,
Macfarlane
,
G.
,
Fleming
,
A.
, and
Leong
,
Z.
,
2017
, “
Scaling and Air Compressibility Effects on a Three-Dimensional Offshore Stationary OWC Wave Energy Converter
,”
Appl. Energy
,
189
, pp.
1
20
.
16.
Elhanafi
,
A.
,
Macfarlane
,
G.
, and
Ning
,
D.
,
2018
, “
Hydrodynamic Performance of Single–Chamber and Dual-Chamber Offshore–Stationary Oscillating Water Column Devices Using CFD
,”
Appl. Energy
,
228
, pp.
82
96
.
17.
Shalby
,
M.
,
Elhanafi
,
A.
,
Walker
,
P.
, and
Dorrell
,
D. G.
,
2019
, “
CFD Modelling of a Small-Scale Fixed Multi-chamber OWC Device
,”
Appl. Ocean Res.
,
88
, pp.
37
47
.
18.
Yoo
,
S. O.
,
Kim
,
H. J.
,
Lee
,
D. Y.
,
Kim
,
B.
, and
Yang
,
S. H.
,
2019
, “
Experimental and Numerical Study on the Flow Reduction in the Moonpool of Floating Offshore Structure
,”
ASME J. Offshore Mech. Arct. Eng.
,
141
(
1
), p.
011301
.
19.
Opoku
,
F.
,
Uddin
,
M. N.
, and
Atkinson
,
M.
,
2023
, “
A Review of Computational Methods for Studying Oscillating Water Columns—The Navier-Stokes Based Equation Approach
,”
Renewable Sustainable Energy Rev.
,
174
, p.
113124
.
20.
Ansys Fluent
,
2015
, Multiphase Modeling Using ANSYS Fluent, Lecture 3: Volume of Fluid Model (VOF).
21.
Hirt
,
C. W.
, and
Nichols
,
B. D.
,
1981
, “
Volume of fluid (VOF) Method for the Dynamics of Free Boundaries
,”
J. Comput. Phys.
,
39
(
1
), pp.
201
225
.
22.
Peric
,
M.
,
2018
, Best Practices for Wave Flow Simulations. The Naval Architect, Feb. 2018.
23.
Fenton
,
J. D.
,
1985
, “
A Fifth-Order Stokes Theory for Steady Waves
,”
J. Waterw. Port, Coast. Ocean Eng.
,
111
(
2
), pp.
216
234
.
24.
ITTC
,
2011
, Recommenced Procedures and Guidelines, Practical Guidelines for Ship CFD Applications.
25.
Chakrabarti
,
S. K.
,
1994
,
Offshore Structure Modeling
,
World Scientific Publishing
,
Singapore
.
26.
Roache
,
P. J.
,
1997
, “
Quantification of Uncertainty in Computational Fluid Dynamics
,”
Annu. Rev. Fluid Mech.
,
29
(
1
), pp.
123
160
.
27.
Molin
,
B.
,
2001
, “
On the Piston and Sloshing Modes in Moonpools
,”
J. Fluid Mech.
,
430
, pp.
27
50
.
You do not currently have access to this content.