Abstract
Time-frequency distribution of axial velocity of spiral flow has been clearly obtained by discrete wavelet transform and multiresolution analysis. As a result, both of the low frequency level and high frequency level of the spiral flow are lower than those of the typical turbulence flow. It means that the turbulence level of the spiral flow is dramatically lower than the typical turbulence flow. Moreover, the dominant frequency level to lower the turbulence level of spiral flow is clarified. The originality of this paper lies in applying discrete wavelet transform and its multiresolution analysis to analyzing the spiral flow.
