scholarly journals Numerical study of a well boat operating at a fish farm in current

2019 ◽  
Vol 84 ◽  
pp. 77-96 ◽  
Author(s):  
Yugao Shen ◽  
Marilena Greco ◽  
Odd M. Faltinsen
Keyword(s):  
Numerical Study ◽  
Fish Farm

scholarly journals Numerical Study on the Heading Misalignment and Current Velocity Reduction of a Vessel-Shaped Offshore Fish Farm

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Lin Li ◽  
Zhiyu Jiang ◽  
Jungao Wang ◽  
Muk Chen Ong
Keyword(s):  
Numerical Study ◽  
Single Point ◽  
Fish Farm ◽  
Misalignment Angle ◽  
Fish Welfare ◽  
Integrated Method ◽  
Waves And Currents ◽  
Spread Area ◽  
Fish Cages ◽  
Current Reduction

Recently, the concept of a vessel-shaped fish farm was proposed for open sea applications. The fish farm comprises a vessel-shaped floater, five fish cages, and a single-point mooring system. Such a system weathervanes, and this feature increases the spread area of fish waste. Still, the downstream cages may experience decreased exchange of water flow when the vessel heading is aligned with the current direction, and fish welfare may be jeopardized. To ameliorate the flow conditions, a dynamic positioning (DP) system may be required, and its power consumption should relate to the heading misalignment. This paper proposes an integrated method for predicting the heading misalignment between the vessel-shaped fish farm and the currents under combined waves and currents. A numerical model is first established for the fish farm system with flexible nets. Current reduction factors are included to address the reduction in flow velocity between net panels. The vessel heading is obtained by finding the equilibrium condition of the whole system under each combined wave and current condition. Then, the Kriging metamodel is applied to capture the relation between the misalignment angle and environmental variables, and the probability distribution of this misalignment angle is estimated for a reference site. Finally, the requirement for the DP system to improve the flow condition in the fish cages is discussed.

Numerical Analysis of a Floating Fish Cage With Feeding Systems

2020 ◽  
Author(s):  
Lin Li ◽  
Mathias Bruset ◽  
Muk Chen Ong ◽  
Xiaopeng Wu
Keyword(s):  
Environmental Conditions ◽  
Numerical Study ◽  
Coupled System ◽  
Feeding Tube ◽  
Fish Farm ◽  
Dynamic Responses ◽  
Feeding System ◽  
Solidity Ratio ◽  
Sensitivity Studies ◽  
Fish Cages

Abstract A modern marine-based fish farm normally consists of a feeding barge, several fish cages, and feeding tubes. Although many studies, both experimental and numerical, are available in the literature to investigate the global responses of the fish cages under wave and current conditions, research on the coupled system including both the fish cage and the feeding system is very limited. This paper presents a numerical study on the coupled system with a floating fish cage and the feeding system. The purpose is to study the dynamic responses of the coupled system under different environmental conditions and configurations of the fish farm. A numerical model is firstly established in the numerical program OrcaFlex, comprising of a feeding barge, a gravity-based floating fish cage with mooring systems, and a feeding tube between the barge and the cage. Time-domain simulations of this coupled system are then performed under environmental conditions corresponding to 1-year and 50-year return periods for a reference site. The deformation of the fish cage, the tensions in the anchor lines and in the feeding tube are compared under various conditions. Sensitivity studies on the solidity ratio of the fish net as well as the lengths of the feeding tube are addressed, and their influences on the responses of the coupled system are also discussed.

Experimental and numerical study of a semi-submersible offshore fish farm under waves

2021 ◽  
Vol 225 ◽  
pp. 108794
Author(s):  
Yu-ji Miao ◽  
Jun Ding ◽  
Chao Tian ◽  
Xu-jun Chen ◽  
Ya-li Fan
Keyword(s):  
Numerical Study ◽  
Fish Farm

A Numerical Study of the Hydrodynamics of an Offshore Fish Farm Using REEF3D

2021 ◽  
Author(s):  
Gang Wang ◽  
Tobias Martin ◽  
Liuyi Huang ◽  
Hans Bihs
Keyword(s):  
Numerical Study ◽  
Structural Response ◽  
Rigid Body Dynamics ◽  
Fish Farm ◽  
Frame Structure ◽  
Wave Loads ◽  
Aspect Ratios ◽  
Free Decay ◽  
Decay Test ◽  
Structural Parts

Abstract In this paper, the CFD framework REEF3D is utilized to investigate the hydrodynamics of a large offshore fish farm in waves. The solver consists of a rigid body dynamics solver for the frame structure coupled to a fluid solver including the shielding effects of the nets. The solver and the grid independence are validated using a 2D numerical wave tank, a free decay test, and a study of the wave loads on a rigid net panel. Then, the effects of regular wave parameters, the thickness of the vertical outer columns of the structure, and varies aspect ratios on the loads, response and maximum mooring tensions are investigated. It is concluded that the response is sensitive to the wave period rather than the wave height and that the net system accounts for about 30% of the total drag but does not influence the structural response to a larger extend. The effect of the aspect ratio on the hydrodynamics is more distinct than that of the frame thickness especially. Thus, the first step towards a systemic evaluation of the importance of different structural parts of an offshore fish cage for the expected responses is presented in this paper.

A numerical study of the hydrodynamics of an offshore fish farm using REEF3D

2021 ◽  
pp. 1-10
Author(s):  
Gang Wang ◽  
Tobias Martin ◽  
Liuyi Huang ◽  
Hans Bihs
Keyword(s):  
Numerical Study ◽  
Structural Response ◽  
Rigid Body Dynamics ◽  
Fish Farm ◽  
Frame Structure ◽  
Wave Loads ◽  
Linear Interaction ◽  
Aspect Ratios ◽  
Decay Test ◽  
Steep Waves

Abstract In this paper, the hydrodynamics of and non-linear interaction between the large offshore fish farm “ShenLan 1” and regular waves are investigated using the open-source CFD toolbox REEF3D. The framework consists of a rigid body dynamics solver for the frame structure coupled to a fluid solver including the shielding effects of the nets. The solver and grid independence are validated using a 2D numerical wave tank, a free decay test and a study of the wave loads on a rigid net panel. Then, the effects of regular wave parameters, the thickness of the vertical outer columns of the structure, and the variations of the aspect ratios on the loads, responses and maximum mooring tension forces are studied. It is concluded that the response motion is sensitive to the wave period rather than the wave height due to the longer duration of unidirectional wave loads acting on the frame. The frequent events of partial submersions and wave overtopping in rather steep waves are confirmed through the capturing of the free surface. The net system accounts for about 30% of the total drag but does not influence the structural response to a larger extend. The effect of the aspect ratio on the hydrodynamics is more distinct than that of the frame thickness. As a result of the study, the first step towards a systemic evaluation of the importance of different structural parts of an offshore fish cage for the expected responses is provided.

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
Sign in / Sign up

Export Citation Format

Share Document