Spatial-spectral Hamiltonian Boussinesq Wave Simulations

This contribution concerns a specific simulation method for coastal wave engineering applications. As is common to reduce computational costs the flow is assumed to be irrotational so that a Boussinesq-type of model in horizontal variables only can be used. Here we advocate the use of such a model that respects the Hamiltonian structure of the wave equations. To avoid approximations of the dispersion relation by an algebraic relation that is needed for finite element/difference methods, we propose a spatial-spectral implementation which can model dispersion exactly for all wave lengths. Results with a relatively simple spatial-spectral implementation of the advanced theoretical model will be compared to experiments for harmonic waves and irregular waves over a submerged trapezoidal bar and bichromatic wave breaking above a flat bottom; calculation times are typically less than 25% of the physical time in environmental geometries.