2D Model of floating breakwater dynamics under linear and non-linear waves

This note describes an example of full fluid structure interaction. The 2D dynamics of a box-type pile-anchored floating breakwater is solved by means of two models using Comsol Multiphysics as finite element solver. The first model is based on the irrotational flow hypothesis and solves the stationary potential problem on a fixed grid, applying linear boundary conditions at the free surface. The second model, still in a preliminary set-up stage, is based on the Navier Stokes equations on a moving grid and the floating body position is obtained solving at each time step a Mass-spring ordinary differential equation that derives the wave forces from the hydrodynamic solution. Simulated wave transmission and vertical displacements of the floating breakwater agree well with physical model results.