Experimental investigation of weakly three-dimensional nonlinear wave interactions

The properties of surface waves coalescing and spreading directionally is presented where two identical wave trains propagate at an angle to each other and hence interact in an X configuration ranging from near-linear to violent breaking. An event of this type is believed to be one of the foundations of the formation of extreme waves in the open sea. The study involved measuring the wave surface elevation along the channels and hence both frequency spectra and energy were calculated. Comparisons between these data confirm that the directional spread has a significant effect on the nonlinear wave wave interactions, especially for the wave profile and energy loss due to breaking. In general, the greater the approach angle of the two wave trains, the more cross-channel variation there is following breaking and the larger the energy loss during breaking. It is believed that the observed results will provide a helpful preliminary study of full three-dimensional interactions. (C) 2019 Elsevier Masson SAS. All rights reserved.