Recent developments of the applications of polyspectral analysis to transitioning fluid flows

Higher-order spectral analyses of the velocity fluctuations in a transitioning mixing layer are presented. The phase of the auto-bispectrum is used to measure the phase difference between the fundamental and subharmonic modes. The normalized magnitude of the auto-bispectrum is used as an indication of the goodness of the measured phase difference. Wavenumber mismatch of interacting frequency domain components are obtained from the ´cross-correlation´ of the auto-bispectrum at two closely spaced points. Results show that bispectral analysis provide an effective tool to provide crucial information on the transitioning mixing layer.