TRIDIMENSIONAL RIP CURRENT MODELLING

摘要

Low-frequency variability generated by lateral shear instabilities of the coastal circulation may promote stirring and mixing of coastal waters. The question remains open to whether tridimensional transient processes are important for the generation of these instabilities and for surf-shelf exchanges in general. An innovative modeling system with tridimensional wave-current interactions (McWilliams et al., 2004) was designed to investigate transient nearshore currents and interaction between nearshore and innershelf circulations. We present here some validation of rip current modeling in the French coastal zone (Bruneau et al., 2011) using in-situ and remote video sensing. We then proceed to show the benefits of 3D versus 2D modeling for the simulation of mean rip currents and their low-frequency variability. It is concluded that tridimensional nearshore models may provide a valuable and cost-effective alternative to more usual 2D approaches, which miss the vertical flow structure and its nonlinear interaction with the 2D flow. Finally, we provide a preliminary evaluation of our model capabilities for morphodynamic studies.