Orthogonal wavelet-decomposed 3-D vorticity of a turbulent cylinder wake

Abstract

A wavelet multi-resolution technique is applied to analyze the three vorticity components obtained simultaneously using an eight-wire probe in the far wake of a circular cylinder at a Reynolds number of 6000. Using this technique, the vorticity is decomposed into a number of orthogonal wavelet components based on different central frequencies, which correspond to the scales of turbulent structures. The vortical structure of each wavelet component is examined in terms of vorticity variance. The present result shows a relatively large contribution to the longitudinal vorticity variance from the large-scale structures than both to the transverse and to the spanwise vorticity components. The dominant contributions to the vorticity variances are from the intermediate and relatively small-scale structures.