Spatial properties of velocity structure functions in turbulent wake flows

Abstract

In this paper we present experimental evidence that the scaling laws for the velocity structure functions ${S}_{n}(r)=〈[V(x+r)\ensuremath{-}V(x){]}^{n}〉$ $n=2,4,6,8$ hold in various parts of the flow domain. The exponents that characterize the scaling are, however, a function of the position in the wake that is the local strength and ubiquity of coherent structures. This variation is shown to be systematic and considerably exceeds the inaccuracy involved in the determination of the exponents. This is an objective indication of the influence that the organized flow structures and inhomogeneity may have on intermittency. In the analysis we invoke the concept of the extended self-similarity (ESS).