Numerical modelling of the interaction between a fish net and fluid using CFD

Abstract

A numerical model for the determination of the deformed shape of nets under consideration of hydrodynamic loads and elastic twines is presented. The hydrodynamic forces are incorporated using Morison's formula and force coefficients evaluated from experiments. The model is coupled to a CFD fluid model by representing the net 's influence on the fluid as a porous medium. For t his purpose, the volume-averaged Navier-Stokes equations, which include porosity and an additional resistance term, are solved. The source term is calculated from an adapted version of Forchheimer's equation for flow in porous media. A validation part focusing on forces and deformation of a net wall in steady current provides insight into the accuracy of the chosen concept.