Detection of Coherent Vorticity Structures using Time-Scale Resolved Acoustic Spectroscopy
Abstract
We describe here an experimental technique based on the acoustic scattering phenomenon allowing the direct probing of the vorticity field in a turbulent flow. Using time-frequency distributions, recently introduced in signal analysis theory, for the analysis of the scattered acoustic signals, we show how the legibility of these signals is significantly improved (time resolved spectroscopy). The method is illustrated on data extracted from a highly turbulent jet flow : discrete vorticity events are clearly evidenced. We claim that the recourse to time-frequency distributions lead to an operational definition of coherent structures associated with phase stationarity in the time-frequency plane.
Cite
@article{arxiv.chao-dyn/9804010,
title = {Detection of Coherent Vorticity Structures using Time-Scale Resolved Acoustic Spectroscopy},
author = {Christophe Baudet and Olivier Michel and William J. Williams},
journal= {arXiv preprint arXiv:chao-dyn/9804010},
year = {2009}
}
Comments
26 pages, 6 figures. Latex2e format Revised version : Added references, figures and Changed content