Modelling the impact of a time-varying wave angle on the nonlinear evolution of sand bars

Sandy beaches are often characterized by the presence of sand bars, whose characteristics (growth, migration, etc.) strongly depend on the wave conditions (wave height, angle of wave incidence, etc.). This study addresses the impact of a periodically time-varying wave angle of incidence with different time-means on the long-term evolution (order days to months) of sand bars. Model results show that heights of sand bars that form in the case of a time-varying angle around a zero-mean are on average larger than those in the cases of time-varying angles around an oblique mean, particularly for large variations in the angle of wave incidence.