Parameterization of nearshore wave front slope

This study presents an empirical parameterization of wave front slope angle used in the characterization of shoaling and breaking waves in nearshore environment. A large amount of experimental datasets is analyzed for determining possible values of the wave front slope angles. Results indicate that the slope angle increases with wave shoaling and decreases when wave breaks. For the data used here, the maximum slope angle is around 0.8 rad at the breakpoint. Two empirical formulas developed based on data analysis establish relationships between the wave front slope angle and other parameters of engineering interest. Specifically, the first formula expresses the local wave front slope angle as a function of the local wave parameters. The applicability of this formula to regular and random shoaling and breaking waves is verified using extensive datasets. The second formula defines the critical wave front slope angle for wave breaking as a function of the relative water depth and bed slope. This formula is shown applicable to both the first and second breakpoints for regular wave breaking over sloping and barred beaches. A combination of these two formulas provides estimates of the incipient breaking wave heights which are in good agreement with independent experimental data.