Abstract
The turbulent flow field of the natural wind is assumed to be composed of the mean flow and many ranks of eddies, which have the lengths A's and the velocities V's corresponding to their ranks. The movement of eddy which belongs to the n-rank is assumed to be influenced by some mutual actions between eddies. The effect of the mutual actions is assumed to be expressed by the surface friction which has the same form with the Stokes' friction law as follows: W=6πA (A/2)V, where A denotes the eddy viscosity coefficient and equals to ρVA.
Under the assumptionn of the same rate of energy dissipation among all ranks of eddies, the negative five-thirds power law of the eddy-energy spectral function is obtained, and the result is compared with the observation which was carried out in the natural wind.
