Advertisement

Flow Around a Surface-Mounted Finite Cylinder: A Challenging Case for LES

  • S. Krajnović
Part of the Notes on Numerical Fluid Mechanics and Multidisciplinary Design book series (NNFM, volume 97)

Abstract

Results of large eddy simulation of a flow around a cylinder with a finite aspect ratio (length/diameter) of 6 placed on a ground plane, is presented. The Reynolds number based on the inlet velocity and the cylinder diameter is 2×104. The boundary layer thickness at the position of the cylinder is approximately 7 % of the cylinder’s diameter. In addition to the comparison of the time-averaged results with existing experimental data, the instantaneous flow was investigated. The fine mesh LES predicted the vortex shedding frequency in agreement with the experimental observations. Several important flow mechanisms are predicted and explained such as: the downwash of coherent structures from the region above the free end into the near wake or the formation of the alternate vortices in the far wake. Instantaneous flow structures around the cylinder such as horseshoe vortex, Kelvin Helmholtz and hairpin vortices are identified and their influence on the cylinder and the resulting aerodynamic forces is explained.

Keywords

Shear Layer Large Eddy Simulation Coherent Structure Lift Force Horseshoe Vortex 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Afgan, I., Moulinec, C., Laurence, D.: Large eddy simulation of flow over a vertically mounted finite cylinder on a flat plate. In: Conference on Modelling Fluid Flow (CMFF 2006). The 13th International Conference on Fluid Flow Technologies, Budapest, Hungary (2006)Google Scholar
  2. Breuer, M.: A challenging test case for large eddy simulation: high Reynolds number circular cylinder flow. International Journal of Heat and Fluid Flow 21, 648–654 (2000)CrossRefGoogle Scholar
  3. Farivar, D.: Turbulent uniform flow around cylinders of finite length. AIAA Journal 19(3), 275–281 (1981)Google Scholar
  4. Krajnović, S.: Large-Eddy Simulation of the Flow Around a Bluff Body. AIAA Journal 40(5), 927–936 (2002)CrossRefGoogle Scholar
  5. Luo, S.C., Li, L.L., Shah, D.A.: Aerodynamic stability of the downstream of two tandem square-section cylinders. Journal of Wind Engineering and Industrial Aerodynamics 79, 79–103 (1999)CrossRefGoogle Scholar
  6. Mathew, G., et al.: Flow past short circular cylinders with two free ends. Journal of Fluid Mechanics 203, 557–575 (1989)CrossRefGoogle Scholar
  7. Okamoto, S., Sunabashiri, Y.: Vortex Shedding From a Circular Cylinder of Finite Length Placed on a Ground Plane. ASME: Journal of Fluids Engineering 114, 512–521 (1992)Google Scholar
  8. Park, C.-W., Lee, S.-J.: Flow structures around a finite circular cylinder embedded in various atmospheric boundary layers. Fluid Dynamics Research 30, 197–215 (2002)CrossRefGoogle Scholar
  9. Strelets, M.: Private communication. New Technologies & Services, St. Petersburg, Russia (2005)Google Scholar
  10. Zdravkovich, M.M.: Flow around circular cylinders. Fundamentals, vol. 1. Oxford University Press, Oxford (1997)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2008

Authors and Affiliations

  • S. Krajnović
    • 1
  1. 1.Chalmers University of TechnologyGothenburgSweden

Personalised recommendations