Picking-up of Turbulence Coherent Structures with Orthogonal Discrete Wavelet Transformation
Dong Hong · 2007
The coherent structure in turbulence is considered as large-scale structure with certainly intense fluctuation.Through the orthogonal discrete wavelet transformation,we get the discrete wavelet coefficients and use them to define the intermittency coefficients.A threshold of intermittency coefficients is suggested to choose the corresponding wavelet coefficients that will be used to reconstruct the signal,while the wavelet coefficients below the threshold are endowed with zero values.Therefore,the intense fluctuations dominate the coherent structure and the small-scale fluctuations have minimal energy.This character can be applied to determine the characteristic scale of coherent structure,and is called the minimal energy ratio principle.