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On the wake with and without vortex shedding suppression behind a two-dimensional square cylinder in proximity to a plane wall
- Source :
-
Journal of Wind Engineering & Industrial Aerodynamics . Oct2010, Vol. 98 Issue 10/11, p492-503. 12p. - Publication Year :
- 2010
-
Abstract
- Abstract: A comparative study of the wake characteristics behind a two-dimensional square cylinder in proximity to a plane wall was made on two systems, i.e. G/D=0.25 and 0.5, which corresponds to the wakes with and without suppression of the vortex shedding, respectively. Here, G is the gap distance and D is the width of the square cylinder. Synchronized measurements of wall-pressure fluctuations and velocity fluctuations were made using a microphone array and a split-fiber film, respectively. For the system G/D=0.5, a regular Karman-like vortex shedding at fD/U 0=0.13 was found by inspection of the streamwise velocity spectra. When the gap width is reduced to G/D=0.25, a low-speed separation bubble was formed in the region 4.25<x/D<9.25, while the intermittent existence of large-scale vortices at the reduced frequency fD/U 0=0.116 was identified in the upper shear layer. The convective vortex dynamics were analyzed in terms of the cross-correlation of the wall-pressure fluctuation, coherence and cross-correlation of wall-pressure fluctuations with velocity fluctuations at various positions located at the lower edge of the cylinder (y/D=G/D) and the outer edge of the upper shear layer. The convection velocities of the Karman-like vortices in the system G/D=0.5 was determined to be Uc /U 0=0.64. However, in the system G/D=0.25 the convection velocities before and behind x/D=3.25 were determined to be Uc /U 0=0.32 and 0.64, respectively. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 01676105
- Volume :
- 98
- Issue :
- 10/11
- Database :
- Academic Search Index
- Journal :
- Journal of Wind Engineering & Industrial Aerodynamics
- Publication Type :
- Academic Journal
- Accession number :
- 52304610
- Full Text :
- https://doi.org/10.1016/j.jweia.2010.03.002