Modelling interaction between waves and sea walls using a numerical wave flume

Abstract

    Numerical wave flumes are useful in predicting detailed flow patterns due to wave breaking in the surf zone, which is very important in design of coastal structures. In this study, the CADMAS-SURF model (2001) is used to get insight into cross-shore wave and flow processes in the surf zone, and to some extent, to evaluate the impact of waves to a typical seawall in Vietnam. The model is first verified against Suzuki's (2011) laboratory-scaled experiment, then against a field survey on a barred beach (Eldeberky 2011). The tuneable parameters include porosity of the seabed layer, drag coefficient, and inertia coefficient of the flow in this layer. As CADMAS-SURF includes a k-epsilon turbulence model, certain wave parameters e.g. wave breaking and dissipation do not need to be specified. Simulation is then performed for extreme wave conditions offshore Do-Son beach (Vietnam). Storm waves and water levels are chosen for annual exceedance probabilities of 1%, 3.33%, and 5%. The simulation outputs including water surface profile, wave heights, flow-, and pressure-fields are summarized to show possibly severe impacts on various parts: toe, slope, and crest of the structure.