Modeling porous coastal structures using a level set method based VRANS-solver on staggered grids

Abstract

Several engineering problems in the field of coastal and offshore engineering involve flow interaction with porous structures such as breakwaters, sediment screens, and scour protection devices. In this paper, the interaction of waves with porous coastal structures using an open-source computational fluid dynamics (CFD) model is presented. The fluid flow through porous media is modeled using the Volume-averaged Reynolds-averaged Navier-Stokes (VRANS) equations. Novel improvements to the numerical grid architecture and discretization schemes are made, with a staggered numerical grid for better pressure-velocity coupling and higher-order schemes for convection and time discretization. New interpolation schemes required for the VRANS equations on a staggered grid are implemented. The flow problem is solved as a two-phase problem and the free surface is captured with the level set function. The model is validated by comparing the numerical results to experimental data for different cases such as flow through crushed rock, solitary, and regular wave interaction with a porous abutment and wave interaction with a breakwater considering the three different porous layers. The numerical results are also seen to be highly grid-independent according to the grid convergence study and show a significantly better agreement to experimental data in comparison to current literature.