Research Papers: Ocean Space Utilization

Numerical Analysis of a Vessel-Shaped Offshore Fish Farm

[+] Author and Article Information
Lin Li, Andreas Vangdal Høiland, Muk Chen Ong

Department of Mechanical and
Structural Engineering and Materials Science,
University of Stavanger,
Stavanger 4036, Norway

Zhiyu Jiang

Centre for Research-based Innovation of Marine
Operations (SFI MOVE),
Department of Marine Technology,
Norwegian University of Science
and Technology (NTNU),
Trondheim 7491, Norway
e-mail:  zhiyu.jiang1896@gmail.com

1Corresponding author.

Contributed by the Ocean, Offshore, and Arctic Engineering Division of ASME for publication in the JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING. Manuscript received August 4, 2017; final manuscript received December 12, 2017; published online February 23, 2018. Assoc. Editor: Theodoro Antoun Netto.

J. Offshore Mech. Arct. Eng 140(4), 041201 (Feb 23, 2018) (11 pages) Paper No: OMAE-17-1137; doi: 10.1115/1.4039131 History: Received August 04, 2017; Revised December 12, 2017

The aquaculture industry is aiming to move fish farms from nearshore areas to open seas because of many attractive advantages in the open water. However, one major challenge is to design the structure to withstand the environmental loads due to wind, waves, and currents. The purpose of this paper is to study a vessel-shaped fish farm concept for open sea applications. The structure includes a vessel-shaped hull, a mooring system, and fish cages. The shape of the hull minimizes the wave loads coming from the bow, and the single-point mooring system is connected to the turret at the vessel bow. Such a system allows the whole fish farm to rotate freely about the turret, reduces the environmental loads on the structure and increases the spread area of fish wastes. A basic geometry of the vessel hull was considered and the hydrodynamic properties were obtained from the frequency-domain (FD) analysis. A mooring system with six mooring lines was designed to avoid possible interactions with the fish cages. Time-domain (TD) simulations were performed by coupling the hull with the mooring system. A simplified rigid model of the fish cages was considered. The global responses of the system and the mooring line loads were compared under various wave and current conditions. The effects due to misalignment of wave and current directions on the responses were discussed. Finally, the responses using flexible and rigid net models were compared under steady current conditions.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


Burnell, G. , and Geoff, A. , eds., 2009, New Technologies in Aquaculture: Improving Production Efficiency, Quality and Environmental Management, Elsevier, Cambridge, UK, pp. 895–913.
Tidwell, J. H., ed., 2012, Aquaculture Production Systems, Wiley, Oxford, UK, pp. 3–13. [CrossRef]
Li, P. , Faltinsen, O. M. , and Lugni, C. , 2016, “ Nonlinear Vertical Accelerations of a Floating Torus in Regular Waves,” J. Fluids Struct., 66, pp. 589–608. [CrossRef]
Kristiansen, T. , and Faltinsen, O. M. , 2012, “ Modelling of Current Loads on Aquaculture Net Cages,” J. Fluids Struct., 34, pp. 218–235. [CrossRef]
Moe-Føre, H. , Endresen, P. C. , Aarsæther, K. G. , Jensen, J. , Føre, M. , Kristiansen, D. , Fredheim, A. , Ladder, P. , and Reite, K.-J. , 2015, “ Structural Analysis of Aquaculture Nets: Comparison and Validation of Different Numerical Modeling Approaches,” ASME J. Offshore Mech. Arct. Eng., 137(4), p. 041201. [CrossRef]
Zhao, Y. P. , Li, Y. C. , Dong, G. H. , Gui, F. K. , and Teng, B. , 2007, “ Numerical Simulation of the Effects of Structure Size Ratio and Mesh Type on Three-Dimensional Deformation of the Fishing-Net Gravity Cage in Current,” Aquacultural Eng., 36(3), pp. 285–301. [CrossRef]
Moe-Føre, H. , Ladder, P. , Lien, E. , and Hopperstad, O. , 2016, “ Structural Response of High Solidity Net Cage Models in Uniform Flow,” J. Fluids Struct., 65, pp. 180–195. [CrossRef]
Xu, T. J. , Dong, G. H. , Zhao, Y. P. , Li, Y. C. , and Gui, F. K. , 2012, “ Numerical Investigation of the Hydrodynamic Behaviors of Multiple Net Cages in Waves,” Aquacultural Eng., 48, pp. 6–18. [CrossRef]
Turner, A. A. , Jeans, T. L. , and Reid, G. K. , 2016, “ Experimental Investigation of Fish Farm Hydrodynamics on 1:15 Scale Model Square Aquaculture Cages,” ASME J. Offshore Mech. Arct. Eng., 138(6), p. 061201. [CrossRef]
SalMar, 2016, “ Offshore Fish Farming—A New Era in Fish Farming is on Its Way,” SalMar, Kverva, Norway, accessed Oct. 7, 2017, http://www.salmar.no/en/offshore-fish-farming-a-new-era
SINTEF, 2016, “ Offshore Salmon Fish Farming,” SINTEF, Trondheim, Norway, accessed Sept. 7, 2016, http://www.sintef.no/en/projects/offshore-salmon-fish-farming
Berge, A. , 2017, “ Today, 'Ocean Farm 1' Comes to Froya,” SalmonBusiness, Godvik, Norway, accessed Oct. 20, 2017, http://salmonbusiness.com/today-ocean-farm-1-comes-to-froya/
Stensvold, T. , 2016, “ Arctic Offshore Farming—Riggeksperter i Aker Solutions lanserer nytt merdkonsept,” TU, Oslo, Norway, accessed Sept. 7, 2016, http://www.tu.no/artikler/riggeksperter-i-aker-solutions-lanserer-nytt-merdkonsept/346030
Li, L. , and Ong, M. C. , 2017, “ A Preliminary Study of a Rigid Semi-Submersible Fish Farm for Open Seas,” ASME Paper No. OMAE2017-61520.
Nordlaks, 2015, “ Havfarm,” Nordlaks, Stokmarknes, Norway, accessed Sept. 7, 2016, http://www.nordlaks.no/Om-oss/Havfarm
Standards Norway, 2009, “ NS9415: Marine Fish Farms: Requirements for Design, Dimensioning, Production, Installation and Operation,” Standards Norway, Oslo, Norway, Standard No. NS9415.
NSK Ship Design, 2016, “ NSK - 3417 Offshore Fish Farm,” NSK Ship Design, Harstad, Norway, accessed Sept. 7, 2016, https://www.nskshipdesign.com/designs/aquaculture/fish-farm-2/
Lee, C. H. , 1995, “ WAMIT Theory Manual,” Massachusetts Institute of Technology, Cambridge, MA, pp. 5–12.
Faltinsen, O. M. , 1990, Sea Loads on Ships and Ocean Structures, Cambridge University Press, Cambridge, UK, pp. 37–89.
DNV, 2008, “ WADAM Theory Manual,” Det Norske Veritas, Oslo, Norway, pp. 7–79.
Tian, X. , Ong, M. C. , Yang, J. , and Myrhaug, D. , 2014, “ Large-Eddy Simulation of the Flow Normal to a Flat Plate Including Corner Effects at a High Reynolds Number,” J. Fluids Struct., 49, pp. 149–169. [CrossRef]
DNV, 2010, “ Environmental Conditions and Environmental Loads,” Det Norske Veritas, Oslo, Norway, Standard No. DNV-RP-C205.
Ladder, P. F. , and Fredheim, A. , 2006, “ Dynamic Properties of a Flexible Net Sheet in Waves and Current—A Numerical Approach,” Aquacultural Eng., 35(3), pp. 228–238. [CrossRef]
Lee, C. W. , Lee, J. , and Park, S. , 2015, “ Dynamic Behavior and Deformation Analysis of the Fish Cage System Using Mass-Spring Model,” China Ocean Eng., 29(3), pp. 311–324. [CrossRef]
Moe, H. , Fredheim, A. , and Hopperstad, O. , 2010, “ Structural Analysis of Aquaculture Net Cages in Current,” J. Fluids Struct., 26(3), pp. 503–516. [CrossRef]
Løland, G. , 1991, “ Current Force on and Flow Through Fish Farms,” Ph.D. dissertation, Norwegian Institute of Technology, Trondheim, Norway.
Løland, G. , 1993, “ Current Forces on, and Water Flow Through and Around, Floating Fish Farms,” Aquaculture Int., 1(1), pp. 72–89. [CrossRef]
Ladder, P. F. , and Enerhaug, B. , 2005, “ Experimental Investigation of Forces and Geometry of a Net Cage in Uniform Flow,” IEEE J. Oceanic Eng., 30(1), pp. 79–84. [CrossRef]
Wolfram, J. , 1999, “ On Alternative Approaches to Linearization and Morison's Equation for Wave Forces,” Proc. R. Soc. London A, 455(1988), pp. 2957–2974. [CrossRef]
Shao, Y. , You, J. , and Glomnes, E. B. , 2016, “ Stochastic Linearization and Its Application in Motion Analysis of Cylindrical Floating Structure With Bilge Boxes,” ASME Paper No. OMAE2016-55059.
MARINTEK, 2015, “ SIMO—Theory Manual Version 4.6,” MARINTEK, Trondheim, Norway, pp. 6–126.
MARINTEK, 2015, “ RIFLEX Theory Manual Version 4.6,” MARINTEK, Trondheim, Norway, pp. 3–107.
Newman, J. N. , 1974, “ Second-Order, Slowly-Varying Forces on Vessels in Irregular Waves,” International Symposium on the Dynamics of Marine Vehicles and Structures in Waves, London, pp. 182–186.
Li, L. , Gao, Z. , and Moan, T. , 2015, “ Joint Distribution of Environmental Condition at Five European Offshore Sites for Design of Combined Wind and Wave Energy Devices,” ASME J. Offshore Mech. Arct. Eng., 137(3), p. 031901. [CrossRef]
DNV, 2013, “ Offshore Standard DNV-OS-E301, Position Mooring,” Det Norske Veritas, Oslo, Norway, Standard No. DNV-OS-E301.
MARINTEK, 2016, “ Modelling of Aquaculture Net Cages in SIMA,” MARINTEK, Trondheim, Norway, pp. 4–21.
Høiland, A. V. , 2017, “ Dynamic Analysis of a Vessel-Shaped Fish Farm for Open Sea,” Master's thesis, University of Stavanger, Stavanger, Norway, pp. 70–93.


Grahic Jump Location
Fig. 1

Overview of the vessel-shaped fish farm concept [15]

Grahic Jump Location
Fig. 2

Main geometry of the submerged part of the vessel-shaped fish farm

Grahic Jump Location
Fig. 3

Definition of the angle of attack of a net panel under a steady current

Grahic Jump Location
Fig. 4

Illustration of models 2 and 4 for hydrodynamic analysis in WADAM: (a) M2 panel model with Morison elements on the hull and (b) M4 panel model with Morison elements on the hull and the simplified nets

Grahic Jump Location
Fig. 5

Comparison of the added masses using different models

Grahic Jump Location
Fig. 6

Comparison of the potential damping from model 1 and the linearized drag damping from models 2 to 4

Grahic Jump Location
Fig. 7

Comparison of RAOs in heave, roll, and pitch from models 1 to 4 (wave direction = 135 deg)

Grahic Jump Location
Fig. 8

Illustration of the coupled model (model 4) in simo-riflex for TD analysis with global coordinate system and mooring line numbers

Grahic Jump Location
Fig. 9

Selected response time histories under EC4 using models 2 and 4

Grahic Jump Location
Fig. 10

Comparison of mean drift motions of the global origin (turret center) under all ECs using three models

Grahic Jump Location
Fig. 11

Mean angle difference between the vessel heading and the directions of waves and currents under all ECs

Grahic Jump Location
Fig. 12

Standard deviations of WF and LF components for horizontal motions using three models (for each EC, from left to right the bars correspond to M2, M3, and M4)

Grahic Jump Location
Fig. 13

Comparison of mean, WF and LF components from vertical motions using three models (for each EC, from left to right the three bars corresponds to M2, M3, and M4)

Grahic Jump Location
Fig. 14

Comparison of maximum tension MPM among six mooring lines (models 2 to 4, ECs 1 to 7)

Grahic Jump Location
Fig. 15

Comparison of the tension MPMs under different ECs (numerical model 4)

Grahic Jump Location
Fig. 16

Comparison of mean, WF and LF components for tensions in mooring line 1 using three models (for each EC, from left to right the three bars corresponds to M2, M3, and M4)

Grahic Jump Location
Fig. 17

The flexible fish net model using representative bar elements

Grahic Jump Location
Fig. 18

Illustration of the deformation of flexible nets in steady currents (Sn = 0.2, each bottom weight is 4 tonnes): (a) Uc = 0.2 m/s, (b) Uc = 0.5 m/s, and (c) Uc = 0.8 m/s

Grahic Jump Location
Fig. 19

Mooring line tension and drift motion of the turret center using rigid and flexible net models (for flexible models, Sn = 0.2, and each bottom weight is 4 tonnes)



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In