Journal of Fluid Mechanics

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Flow field around a vibrating cantilever: coherent structure eduction by continuous wavelet transform and proper orthogonal decomposition

Y.-H. KIMa1, C. CIERPKAa2 c1 and S. T. WERELEYa3

a1 Energy Business Department, Growth and Investment Division, POSCO, 892 Daechi 4-dong Gangnam-gu, Seoul 135-777, South Korea

a2 Institute for Fluid Dynamics and Aerodynamics, University of the Federal Arms Munich, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany

a3 Department of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-1288, USA

Abstract

The velocity field around a vibrating cantilever plate was experimentally investigated using phase-locked particle image velocimetry. Experiments were performed at Reynolds numbers of Reh = 101, 126 and 146 based on the tip amplitude and the speed of the cantilever. The averaged vector fields indicate a pseudo-jet flow, which is dominated by vortical structures. These vortical structures are identified and characterized using the continuous wavelet transform. Three-dimensional flow features are also clearly revealed by this technique. Furthermore, proper orthogonal decomposition was used to investigate regions of vortex production and breakdown. The results show clearly that the investigation of phase-averaged data hides several key flow features. Careful data post-processing is therefore necessary to investigate the flow around the vibrating cantilever and similar highly transient periodic flows.

(Received April 27 2010)

(Revised October 04 2010)

(Accepted October 04 2010)

(Online publication February 08 2011)

Key words:

  • shear layers;
  • vortex dynamics;
  • vortex shedding

Correspondence:

c1 Email address for correspondence: christian.cierpka@unibw.de

Footnotes

The first and the second author contributed equally to the paper.

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