On experimental justification of weekly turbulent nature of growing wind seas

The causes of breaking of deep-water two-dimensional waves are studied. Evolution of initially monochromatic steep waves to the point of breaking was first investigated by means of the fully nonlinear Chalikov-Sheinin model. Individual wave steepness is found to be the single most important parameter which determines whether the wave will break immediately, never break or take a finite number of wave lengths to break. If the wind forcing is superimposed, it can alter the wave-breaking dependences, but these effects appear to be of secondary importance. The results were subsequently verified and elaborated in a laboratory experiment. The experiment demonstrated good qualitative agreement with the numerical simulations and consequently the breaking dependences were quantified. Since the location of breaking onset, which occurs as a result of the natural evolution of nonlinear wave trains can thus be controlled, properties of incipient breakers were measured. It was found that the breaking will occur once the wave reaches the Stokes limiting steepness. Potential applications to field conditions are also discussed.