An experimental comparison of velocities underneath focussed breaking waves

• DOI: 10.1016/j.oceaneng.2018.02.049
• Publication Date: 2018-03-02T11:23:03Z
• Authors: Alberto Alberello; Amin Chabchoub; Jason P. Monty; Filippo Nelli; Jung Hoon Lee; John Elsnab; Alessandro Toffoli
• Keywords: Physics - Atmospheric and Oceanic Physics; Atmospheric and Oceanic Physics (physics.ao-ph); FOS: Physical sciences; Pattern Formation and Solitons (nlin.PS); 530; Nonlinear Sciences - Pattern Formation and Solitons; 01 natural sciences; 620; 0105 earth and related environmental sciences

Nonlinear wave interactions affect the evolution of steep wave groups, their breaking and the associated kinematic field. Laboratory experiments are performed to investigate the effect of the underlying focussing mechanism on the shape of the breaking wave and its velocity field. In this regard, it is found that the shape of the wave spectrum plays a substantial role. Broader underlying wave spectra leads to energetic plungers at a relatively low amplitude. For narrower spectra waves break at a higher amplitudes but with a less energetic spiller. Comparison with standard engineering methods commonly used to predict the velocity underneath extreme waves shows that, under certain conditions, the measured velocity profile strongly deviates from engineering predictions.