Wavelet Auto-Correlation Analysis Applied to Flow Structure in a Bounded Jet

Abstract

To investigate the unsteady structure of secondary flow of a turbulent bounded jet in both frequency and physical spaces, the wavelet auto-correlation analysis was used to analyze the fluctuating velocities at various positions in abounded jet. The wavelet auto-correlation analysis provides the auto-correlation characteristics of signals in terms of period and time delay. From the wavelet auto-correlation analysis, the branching structures in WR(a, τ) reveal that a periodic large eddy motion contains the periodic small eddy motions. In the shear layer near the wall at X/b₀=8.0, Y/b₀ =1.0 and Z/b₀=1.9, the wavelet auto-correlation analysis may determine the period and the location of the large-scale structure and the secondary flows.