Abstract:

ESDU 74030 introduces the background to the statistics used for presenting the turbulence data in the Series, explaining the physical significance of the terms used. Only concepts relating to turbulence are introduced and the work is divided into consideration of measurements made at one point as time changes and of measurements made simultaneously at two different points. In the first case the parameters are probability density, covariance functions and spectral density while in the second case the length scales, cross-covariances, and cross-spectral densities and coherence functions are introduced.