Resonant response of harbours to short-wave groups

Abstract

A non-linear short-wave propagation model is used for the simulation of low-frequency waves induced by short-wave groups. The model is based on the higher order Boussinesq-type equations for the propagation of breaking and non-breaking waves in nearshore areas. The 2DH (two horizontal dimensions) Boussinesq model is used to calculate the resonant response of harbours due to bound waves generated by short-wave groups. The results are compared with experimental data available in the literature. In these experiments, bound long waves are generated by carrier bichromatic short waves, which form regular wave groups. The results of the model were found to be in good agreement with the experimental data. The 1DH Boussinesq model is applied in the surf zone to simulate surf beat generation by a time-varying breakpoint and the reflected long wave induced by bichromatic wave groups. A new breaking criterion is introduced, based on the relative trough Froude number. Model generation of the surf beat is also shown to be in good agreement with experimental data.