Using the rasInterFoam CFD model for wave transformation and coastal modelling

It is difficult, using simple models, to model the effects of strong nonlinear waves and breaking waves on coastal and offshore structures. Here, the rasInterFoam CFD code, part of the OpenFOAM library, is used to validate against experimental data for a 3D problem. The experimental data consists of free surface elevation time-series from the impact of non-linear waves on a cylindrical column in shallow water. It is found that results obtained even from relatively coarse meshes can give useful results, with the CFD model able to reproduce the shape and wave spectrum of a focused wave group to reasonable accuracy. It is also found that smaller meshes provide greater accuracy, but that the computational cost of this accuracy is not always justified. It is shown that the computational expense of the method is not prohibitive of its use as a design tool.