Numerical modeling of wave-induced currents using a parabolic wave equation.

摘要

Prediction of waves and currents in the nearshore region in the presence of proposed breakwaters is needed in the design process in order to optimize the placement of the structures. A numerical model is developed which solves for the wave field, the depth averaged mean currents and the mean water surface elevation within a given computational domain with the presence of breakwaters. The model iterates between a wave model and a circulation model. The wave model uses a parabolic approximation to a combined refraction-diffraction mild slope equation which includes currents. The circulation model uses an alternating direction implicit method solution to the depth averaged equations of momentum using the radiation stress terms obtained through solution of the wave model as the forcing terms. Each of the terms in the depth averaged equations of momentum involve assumptions that are discussed in the report. The model is constructed in modular form so that improvements can easily be incorporated into the model.;The model was employed for several test cases such as rip channels, bar gaps, and both shore perpendicular and shore parallel breakwaters. Good agreement was obtained when the model was used to simulate a laboratory experiment of Michael R. Gourlay ("Wave set-up and wave generated currents in the lee of a breakwater or headland," Proc.14;Suggestions are made for improving the model and for including sediment transport in the model.