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Wavelet spectrum analysis on energy transfer of multi-scale structures in wall turbulence

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  • Tianjin Key Laboratory of Modern Engineering Mechanics, Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300072, P. R. China

Received date: 2008-09-25

  Revised date: 2008-11-04

  Online published: 2009-04-16

Abstract

The streamwise velocity components at different vertical heights in wall turbulence were measured. Wavelet transform was used to study the turbulent energy spectra, indicating that the global spectrum results from the weighted average of Fourier spectrum based on wavelet scales. Wavelet  transform with more vanishing moments can express the declining of turbulent spectrum. The local wavelet spectrum shows that the physical phenomena such as deformation or breakup of eddies are related to the vertical position in the boundary layer, and the energy-containing eddies exist in a multi-scale form. Moreover, the size of these eddies increases with the measured points moving out of the wall. In the buffer region, the small scale energy-containing eddies with higher frequency are excited. In the outer region, the maximal energy is concentrated in the low-frequency large-scale eddies, and the frequency domain of energy-containing eddies becomes narrower.

Cite this article

Zhen-Tan XIA;Yan TIAN;Nan JIANG . Wavelet spectrum analysis on energy transfer of multi-scale structures in wall turbulence[J]. Applied Mathematics and Mechanics, 2009 , 30(4) : 435 -443 . DOI: 10.1007/s10483-009-0404-8

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