Abstract:
We present a series of complementary physical experiments and numerical model simulations based on a coupled Boussinesq-nonlinear shallow water equation scheme to investigate extreme wave runup on a plane beach. Extreme incident waves are modelled as focused wave groups using the NewWave design wave, and the maximum runup elevations generated by these focused waves are compared to the extreme runup elevations recorded during related irregular wave runup simulations. The maximum runup of a focused wave group exhibits strong dependence on the linear amplitude, focus location and phase at focus of the focused wave group. The extreme values of irregular wave runup in a random sea compare well to the runup values from equivalent incident focused wave groups with amplitudes set with Rayleigh statistics and optimised focus position and phase.