Tridimensional nonhydrostatic transient rip currents in a wave-resolving model

Flash rips and surf eddies are transient horizontal structures of the order 10 to 100 m, which can be generated in surfzone absence bathymetric irregularities. They traditionally evaluated a depth averaged setting involves intrinsic shear instabilities direct generation vorticity by short-crested waves. In this article, we revisit processes eddy with new three-dimensional wave resolution model (CROCO) provide plausible demonstration 3D non-hydrostatic instability turbulent cascade. We first present quick overview compressible free surface approach suitable for nearshore dynamics. Its ability simulate propagation gravity waves wave-driven circulation is validated two laboratory experiments. Next, real world application from Grand Popo Beach, Benin, forced frequency directional spreading. The differs depth-averaged models, due vertical associated shallow breaking case, both hampered, former stretching alongshore current latter inhibiting inverse energy Instead, flow subjected group variability Kelvin–Helmholtz type at an inflection point. Primary secondary generate spanwise streamwise connecting small-scale larger structures. Streamwise filaments, appearing as 5 m wide ribs or mini-rips, extend beyond but moderate energy. These results appear consistent velocity spectra observed patterns tracers suspended sediments Beach. timescale mean shear-induced turbulence several times period suggests intermediate range between breaker-induced large-scale eddies.