Surf hydrodynamics under collapsing coastal dunes

The hydrodynamics of the surf zone in front of collapsing coastal dunes are examined. The data was gathered during the HYDRALAB-III funded Transnational Access experiment performed at the CIEM large-scale wave flume. Here, it is presented results of the cross-shore evolution of several flow parameters at four positions. Despiked and band-pass filtered ADV velocity data were used to enable a focus on only the short-wave component. As the waves approach the shore they reduce their (velocity) skewness, but increase their vertical asymmetry. Despite the non-negligible wave reflection, the theoretical wave model of Abreu et al. (2010) was applied to successfully reproduce the measured velocities. Lastly, an estimate of the bed shear stress exerted by the shortwave components is presented.