Numerical Investigation on Different Configurations of Offshore Fish Cages in Submerged Conditions Subjected to Regular Waves

Abstract

The present research work concerns about the hydrodynamic behaviors of the open net offshore fish cages of single, double and 4-cage systems subjected to regular sinusoidal waves. The open net semisubmersible rigid cage is square in shape and analyzed numerically using ANSYS AQWA software. Frequency and time domain analyses are carried out for each case. The hydrodynamic parameters such as added mass, radiation potential damping, motion responses and mooring line tensions are considered as performance indicators to conclude as the best arrangements among three different cages. The single cage and windward side of all cages exhibit identical performance in all hydrodynamic parameters. The leeward side of each cage shows lesser parametric values than the windward side cages. Based on the performance indicators, it is concluded that the grid system containing four cage arrangements provides better performance than three other cage configurations. An experimental model of 1: 75 scale is fabricated and wave flume studies are conducted to validate the present numerical model. The cage is placed at a water depth of 55 cm and subjected to wave heights of 12 cm and 14 cm with wave periods ranging from 0.8 s to 2.2 s with an interval of 0.2 s are considered. The same wave flume boundary conditions are adopted for numerical simulations and results are in good agreement with experimental work results.

Keywords

Hydrodynamic analysis / Offshore cages / Semisubmersible cages / Cage arrangements / ANSYS AQWA

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