Renewable Energy, 5th Edition

Figure 3.52 Fetch-limited energy spectrum of waves in the southern part of the North Sea. The wind is blowing from the continental shore (westward from Helgoland). Based on Hasselmann et al. (1973).

The position of the spectral peak will move downward as a function of time owing to non-linear wave–wave interactions, i.e., interactions between different spectral components of the wave field, as discussed in connection with (2.81) (Hasselmann, 1962). This behavior is clearly seen in the laboratory experiments of Mitsuyasu (1968), from which Fig. 3.53 shows an example of the time derivative of the energy spectrum, ∂F₁(ν)/∂t. Energy is transferred ...