Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/10374
Title: Effects of the corner radius on the near wake of a square prism
Authors: Hu, JC
Zhou, Y
Dalton, C
Issue Date: 2006
Publisher: Springer
Source: Experiments in fluids, 2006, v. 40, no. 1, p. 106-118 How to cite?
Journal: Experiments in Fluids 
Abstract: The near wake of square cylinders with different corner radii was experimentally studied based on particle imaging velocimetry (PIV), laser doppler anemometry (LDA) and hotwire measurements. Four bluff bodies, i.e., r/d=0 (square cylinder), 0.157, 0.236, 0.5 (circular cylinder), where r is corner radius and d is the characteristic dimension of the bluff bodies, were examined. A conditional sampling technique was developed to obtain the phase-averaged PIV data in order to characterize quantitatively the effect of corner radii on the near-wake flow structure. The results show that, as r/d increases from 0 to 0.5, the maximum strength of shed vortices attenuates, the circulation associated with the vortices decreases progressively by 50%, the Strouhal number, St, increases by about 60%, the convection velocity of the vortices increases along with the widening of the wake width by about 25%, the vortex formation length and the wake closure length almost double in size. Meanwhile, both the vortex wavelength, λ x , and the lateral spacing, λ y , decrease as r/d increases, but the ratio of λ y to λ x is approximately 0.29, irrespective of r/d, which is close to the theoretical value of 0.281 for a stable Karman vortex street. The decrease in wavelength is probably responsible for the change in the flow structure from the approximately circular-shaped vortex at r/d=0 to the laterally stretched vortex at r/d=0.5. The leading edge corner radius is more important than the trailing one in influencing the near wake structure since it determines to a great extent the behavior of the streamlines, the separation angle and the base pressure. It is further found that the ratio of the mean drag coefficient to the total shed circulation, C d/Γ0, approaches a constant, about 0.25 for different bluff bodies in the subcritical flow regime. The streamwise evolution of vortices and the streamwise fluctuating velocity along the centerline for rounded cylinders are also discussed.
URI: http://hdl.handle.net/10397/10374
ISSN: 0723-4864
DOI: 10.1007/s00348-005-0052-2
Appears in Collections:Journal/Magazine Article

Access
View full-text via PolyU eLinks SFX Query
Show full item record

SCOPUSTM   
Citations

51
Last Week
0
Last month
1
Citations as of May 27, 2017

WEB OF SCIENCETM
Citations

45
Last Week
1
Last month
0
Citations as of May 21, 2017

Page view(s)

25
Last Week
0
Last month
Checked on May 28, 2017

Google ScholarTM

Check

Altmetric



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.