Angular distribution effect on weakly nonlinear energy transfer in the spectrum of wind waves

The effect of angular distribution on weakly nonlinear energy transfer in t he spectrum of wind waves is studied, By using the numerical integration te chniques of the highest accuracy, reliable results concerning a weakly nonl inear energy transfer are obtained for the most representative approximatio ns of wind wave spectra. It is shown that a weakly nonlinear energy transfe r is different from zero in a wide frequency-angle region. Calculation resu lts point to the existence of weakly nonlinear energy transfer to the spect ral components traveling in opposition to the wind direction, The theoretic al studies provide an explanation for the measured wind-wave spectrum conta ining spectral components traveling in opposition to the wind.