RANS simulations of surf zone hydrodynamics using Reynolds stress transport equations

The surf zone, situated at the beach where waves break, hosts various hydrodynamic phenomena, including waves, surface rollers (recirculating flow on the wave's front), and undertows. These phenomena have a substantial impact on beach evolution.  In this study, a Reynolds-averaged Navier-Stokes numerical model with Reynolds stress equations is applied to simulate the hydrodynamics of the surf zone. The air-water interface is captured using the volume of fluid method. To validate the numerical model, comparisons are made between the simulated results and measured ones from prototype experiments. The study extends to the analysis of wave energy, surface roller energy, and undertow dynamics. Furthermore, the numerical results are used to assess the effectiveness of a surf zone model based on the wave action equation, roller energy equation, and shallow water equation. This comprehensive approach enhances our understanding of the complex interactions within the surf zone and provides valuable insights for coastal engineering.