[A-OS15] Waves, Storm Surges, and Related Hazards

[AOS15-P04] Extreme wave statistics in the presence of wave reflection

Yuchen He¹, Ana Vila-Concejo¹, Alexander V. Babanin², Alexey Slunyaev³, Nobuhito Mori ⁴, *Amin Chabchoub^4,1 (1.The University of Sydney, 2.The University of Melbourne, 3.Institute of Applied Physics RAS Nizhny Novgorod , 4.Kyoto University)

Keywords:Extreme Waves , Nonlinear Waves

Rogue waves are known to appear in various water depth regimes and their focusing mechanisms have been intensively studied over the last decades. On the other hand, little attention has been paid to complex extreme wave processes near shorelines. This experimental study aims to improve understanding of rogue wave physics and statistics when wave reflections are at play. Uni-directional JONSWAP wave trains with representative significant wave heights and spectral bandwidths have been generated in a wave flume while varying the artificial beach material and inclination. The data collected near the beach installation suggests a decrease of extreme wave probability with the increase of the beach inclination. Numerical simulations based on the hydrodynamic coupled nonlinear Schrödinger equation, which accounts for the presence of reflective waves, show a very good agreement with the experimental data. The measurements indicate that the decrease of probability of exceedance correlates with the decrease of the value of kurtosis for all cases considered. Nevertheless, we confirm the relevance of wave nonlinearity and modulation instability in the formation of extreme events in such set-ups, particularly for the case of pure standing waves.