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A numerical study of geometrical effects on the strouhal number of a circular cylinder

Kazemifar, F ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1115/IMECE2008-69034
  3. Publisher: 2009
  4. Abstract:
  5. In this paper, reducing the Strouhal number of a circular cylinder is studied numerically. Two-dimensional numerical simulations of flow over a normal circular cylinder and various modified circular cylinders are carried out using FLUENT® soft ware. Two small blades are attached to a circular cylinder and the effects of variation of the blades length and the blade angle are studied numerically. The blade angle is chosen 2α=0°, 30°, 90°, 120° and 150°. The blades length is chosen l/d=0.125, 0.25, 0.375. Effects of blade angles and blade lengths were studied for both 2α=0° and 150°. Results show that increasing in blade lengths decreases the Strouhal number. Moreover, as the blade angle was increased from zero to 90°, the percentage reduction in Strouhal number decreased; however, as the blade angle was further increased from 90° to 150°, the percentage reduction in Strouhal number increased. Although the modifications studied here decrease the vortex shedding frequency they make the vortices shed from the cylinder farther and stronger hence increasing the magnitude of the fluctuating forces. Copyright © 2008 by ASME
  6. Keywords:
  7. Circular cylinder ; Blade angle ; Fluctuating forces ; Geometrical effect ; Numerical studies ; Two-dimensional numerical simulation ; Vortex shedding frequency ; Computer simulation ; Mechanical engineering ; Strouhal number ; Turbomachine blades ; Vortex flow ; Vortex shedding ; Circular cylinders
  8. Source: 2008 ASME International Mechanical Engineering Congress and Exposition, IMECE 2008, Boston, MA, 31 October 2008 through 6 November 2008 ; Volume 1 , 2009 , Pages 57-66 ; 9780791848623 (ISBN)
  9. URL: https://asmedigitalcollection.asme.org/IMECE/proceedings-abstract/IMECE2008/48623/57/334811