Improving the Simulation of Depth-induced Breaking in the Third-Generation Wave Model SWAN

In this study, the default wave breaking term in the SWAN numerical model and the depth-induced breaking term presented by Thornton and Guza (1983) were investigated. It was shown that by modifying the coefficients in the Thornton and Guza pattern, the simulation of waves in shallow water can be improved. To evaluate the model performance, several waves were generated in 3 depths, periods and heights in the laboratory. The corresponding condition were simulated by the SWAN numerical model, and the wave heights generated in the laboratory were compared with the model results. Two main calibration parameters in the Thornton and Guza model were tuned in different scenarios, and the improvement of SWAN in simulating the waves was assessed in each scenario. Finally, some formula for calibration parameters were proposed to be implemented in the SWAN numerical model, which resulted in a significant improvement in the calculation of depth-induced breaking of random waves.