Effect of directionality on extreme wave formation during nonlinear shoaling

Abstract

Recent studies have shown that, in coastal waters where water depth decreases significantly due to rapid bathymetric changes, the non-equilibrium dynamics (NED) substantially increases the occurrence probability of extreme (rogue) waves. Nevertheless, research on depth-induced NED has been predominantly confined to unidirectional irregular waves, while the role of directionality remains largely unexplored. The scarce studies on multidirectional waves mainly rely on numerical simulations and have yielded conflicting results. In this work, we report on an experimental investigation of wave directionality on the depth-induced non-equilibrium wave statistics. High-order statistical moments, skewness and kurtosis, are used as proxies for the non-equilibrium wave response. Our results indicate that the directional spreading has a minor effect on decreasing the maximum values of these statistical moments. In contrast, the incidence direction plays a significant role in the non-equilibrium wave response, which is attributed to the effective bottom slope.

References in corpus (6)

• Wind generated rogue waves in an annular wave flume
• Anomalous wave statistics induced by abrupt depth change
• Experimental evidence of nonlinear focusing in standing water waves
• Experimental study of breathers and rogue waves generated by random waves over non-uniform bathymetry
• Effect of shoaling length on rogue wave occurrence
• Symmetric influence of forward and opposing tidal currents on rogue wave statistics