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 6 000. 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.

Wavelet analysis of unsteady flows: Application on the determination of the Strouhal number of the transient wake behind a single cylinder

“…For the interpretation of switching flows, wavelet analysis in addition to Fourier analysis was used [19,20]. Wavelet transforms were also used to study the vorticity structure in the far wake downstream of a cylinder [21,22], transient phenomena in tube banks [23] and the bistable flows in tube banks [24].…”