DOI: 10.1615/TSFP2
CVS FILTERING OF TURBULENT MIXING LAYERS USING ORTHOGONAL WAVELET DECOMPOSITION
RÉSUMÉ
In the present paper we apply the Coherent Vortex Simulation (CVS) filtering to a turbulent mixing layer computed by high resolution Direct Numerical Simulation (DNS). The CVS filtering is based on an orthogonal wavelet decomposition of the vorticity field and a nonlinear thresholding of the wavelet coefficients. The threshold is motivated from optimal denoising theory and only depends on the enstrophy and on the Reynolds number. The presented results show that the coherent part corresponding to the strong wavelet coefficients contains the vortex tubes which reproduce the vorticity PDF and the energy spectrum over the entire inertial range. The remaining incoherent background flow is homogeneous, structurelss, has small amplitude, and is uncorrelated.