Justification of the Inertial Dissipation Technique in Anisotropic Mean Flow

ISSN： 0006-8314

Source： Boundary-Layer Meteorology, Vol.88, Iss.2, 1998-08, pp. : 161-180

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The inertial dissipation technique has been successfully employed for many years to measure the wind stress, especially over the open ocean. This method is based on Kolmogorov's theoretical prediction of universality in the inertial wavenumber range. The theory was developed under the assumption of locally isotropic turbulence, and the dissipation technique has been criticized as lacking justification in a boundary-layer shear flow. In this paper, Kolmogorov's theory is explicitly applied to the anisotropic conditions prevailing in the atmosphere. It is shown that the inertial dissipation method relies on the homogeneity and isotropy of the spectrum _ii(k) for k in the inertial range. This is a weaker condition than Kolmogorov's assumption of isotropy of the correlation function B_ij(r). In high-Reynolds-number shear flows, isotropy of _ii(k) is realized to a good approximation, whereas isotropy of B_ij(r) is not. Some consequences for the experimental implementation are discussed; in particular, sampling times (block lengths) not exceeding the order of the eddy life time are recommended in the calculation of spectra.