Flow through fish farming sea cages: Comparing computational fluid dynamics simulations with scaled and full-scale experimental data

Computational fluid dynamics (CFD) simulations were performed on the flow through and around full-scale sea cages. The Reynolds average Navier-Stokes equations were solved using a finite volume approach. The realizable k−ϵ model was used to describe turbulence and porous media to represent the flow resistance effect of the net. Velocity deficit was investigated for a single cage, a row of five cages, and two rows of five cages, corresponding to the salmon farm at Gulin in the Faroe Islands. CFD simulations were compared with field measurement data from this farm. The comparison showed that the flow was overpredicted with up to 50% by the CFD simulations using a net solidity corresponding to the net specifications. A hypothesis is presented for the discrepancy between CFD simulations and field measurements, which includes net deformation and fish behavior. Using different cage layouts, different distances between cage centres, and different net soldities, the effects on flow through and around sea cages were examined and discussed.