Laboratory investigation of the impact of long waves on small-scale wind waves
Résumé
The effects of mechanically-generated long waves on wind-generated waves of shorter scales are investigated in laboratory as function of the different wind and long wave parameters. The modulation of short waves both in energy and scales along the long wave profiles is estimated respectively by means of the wavelet decomposition and the classical windowed Fourier transform methods, and the results are analysed within the framework of the recent coupled air-flow theories. The noticeable damping of the dominant waves in presence of a long wave is then quantified at the different stages of the wind wave field development. The relevant nonlinear mechanisms at the origin of these phenomena are discussed in the light of these observations.