An implicit Eulerian–Lagrangian model for flow-net interaction using immersed boundary method in OpenFOAM

Abstract

In this paper, we propose an implicit Eulerian–Lagrangian model to resolve the fluid–structure interaction of submerged nets. The Reynolds-averaged Navier–Stokes equations are solved on an Eulerian grid using OpenFOAM and the geometry of the flexible net structures is tracked using Lagrangian points. The motion and deformation of the flexible net structures are advanced using an implicit scheme to avoid excessively small time intervals. The force acting on the net structures is calculated based on a mass–spring system. The screen model and the immersed boundary method are implemented to capture the interaction between the net structures and the surrounding fluid. We present a new drag coefficient formulation as based on a piecewise function for different net solidities to obtain a much improved drag force prediction. The numerical results are compared with a series of existing experiments showing excellent agreement and improved drag force predictions.