Wind waves is no other than free vibration of a water surface. Free vibration always takes the form of a dispersion wave train in Cauchy-Poisson's type. Each wave absorbs energy due to its build from wind, which serves for a negative resistance to the wave motion. This is a kind of self-excited vibration. Accordingly, the wave frequency or the wave length which specifies the fundamental characteristics of the wave obeys the rule of free vibration. Wind is not responsible for the wave length. The height of a wave is, however, settled in balance of natural reduction due to dispersion and amplification by the negative resistance.
