NUMERICAL INVESTIGATIONS ON THE EFFECT OF WAVE SKEWNESS ON SANDBAR MIGRATION

摘要

The morphological evolution of a natural beach characterized by large alongshore-uniform sandbars is numerically investigated. The model consists of a linear spectral refraction-diffraction model, REF/DIF S and a quasi-3D nearshore circulation model, SHORECIRC. The nonlinearities of the near bed orbital velocities are introduced by using a set of empirical equations. A generic energetics-type sediment transport model is incorporated in the model to predict the transport rates and the bathymetric evolution. Offshore (onshore) bar migration is predicted for non-skewed (skewed) wave conditions. It is observed that the near bed orbital velocity skewness due to nonlinearities contributes to the onshore transport of sediment and dominates causing onshore bar migration.