DOI: 10.1615/TSFP6
WAVELET-DECOMPOSED THREE VORTICITY COMPONENTS IN A TURBULENT NEAR WAKE
SINOPSIS
The purpose of the present study is to examine the characteristics of the vortical structures using the orthogonal wavelet multi-resolution technique by decomposing the vorticity into a number of wavelet components based on different central frequencies. The three vorticity components were measured simultaneously using an eight-wire probe in the near wake of a circular cylinder at three Reynolds numbers, namely 1,600, 6,500 and 10,000. It is found that the dominant contributions to the vorticity variances are from the intermediate and relatively small-scale structures. The contributions from the large and intermediate-scale structures to the vorticity variances decrease with the increase of Reynolds number, while the contributions from the small-scale structures to all three vorticity variances jump significantly, which is connected to previous observations in the near wake that there is a significant increase in the generation of smallscale structures. The result reinforces the conception that turbulence 'remembers' its origin.