Inside a Beach Drainage System: A Three-Dimensional Modeling

The capabilities of computational fluid dynamics (CFD) to investigate detailed aspects of a physical phenomenon are here used to study the drainage efficiency of a beach drainage system (BDS)-namely, a low-environmental impact tool for shoreline stabilization. One of the advantages of CFD is its capability to investigate aspects that otherwise would be more difficult to measure experimentally. In this study, a three-dimensional CFD model was used to investigate what happens inside a drain when it is buried in a simplified fine porous domain, when an oscillating groundwater table, forced by regular waves, filters into a draining pipe. The model used was the OpenFOAM (R) solver IHFOAM, which solves the volume-averaged Reynolds-averaged Navier-Stokes equations to simulate flow through fine porous media such as the one in a sandy beach. A parametric study was carried out with respect to the porous medium and the draining surface characteristics as well as the flow regime inside the BDS. Different solutions on the draining surface were considered-namely, different arrangements of the holes through which water flows.