Numerical investigations on fluid characteristics around the bottom-fixed aquacultural farm

Abstract

Offshore aquacultural farms are world widely booming in recent years. The bottom-fixed aquacultural farm gains more and more attention because of the large volume and great strength. This study numerically investigates the fluid velocity distribution characteristic around the bottom-fixed aquacultural farm, which is of great importance for fish welfare and pollutant diffusion. The numerical model is developed based on the porous media model for the nets and the rigid walls for the fixed frame. The k-omega turbulence model and the finite volume method are employed to solve the Navier-Stokes equations. The flow velocity distributions around and inside the farm in the varied current velocity are analyzed. The vertical and horizontal flow velocity distributions in various current directions with different net solidities are investigated in detail. Results demonstrated that the configurations of trusses, vertical and horizontal columns of the farm and the interaction with the nets result in complex velocity distributions inside and around the farm. The velocity attenuations at different depths are quite different in uniform and non-uniform currents. The velocity distributions in different attack angles of the flow provide valuable suggestions on the arrangement and layout of the multiple farms.