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Unsteady Flow Structure Behind A Low-Drag Ahmed Body

  • Yingchao Zhang
  • Bingfu Zhang
  • Yu Zhou
Conference paper
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

Unsteady flow structure behind an Ahmed body with a slant angle of 35°, corresponding to the low-drag regime, has been experimentally investigated at Re of 6.59 × 104. Measurements are conducted using single hotwire and flow visualization techniques. The major flow characteristics are examined. A total of five distinct Strouhal numbers (St) have been identified in the wake, as the case of the high-drag regime. Two detected over the rear window are linked to vortices generated along the roof and side surfaces of the model, respectively, and two found near the ground surface are ascribed to vortices produced by the struts (wheels) of the body. The fifth one, with St = 0.3, captured behind the base is distinct from its counterpart found in the high-drag regime and a physical explanation is proposed for this St.

Keywords

Ahmed body wake Unsteady flow structure Vehicle model Strouhal number 

Notes

Acknowledgements

Authors acknowledge support from the Hong Kong Scholar Program and China Postdoctoral Science Foundation through grants 2012M510874, 2012T50314 and 2014M551180. Supports from Research Grants Council of HKSAR through grant GRF 531912 and from Shenzhen Government through grant JCYJ20130329154125496 are also gratefully acknowledged.

References

  1. 1.
    Tunay T, Sahin B, Ozbolat V (2014) Effects of rear slant angles on the flow characteristics of Ahmed body. Exp Therm Fluid Sci 57(2014):165–176CrossRefGoogle Scholar
  2. 2.
    Zhang BF, To S, Zhou Y (2014) Strouhal numbers of unsteady flow structures around a simplified car model. In: Zhou Y, Liu Y, Huang L, Hodges D (eds) Fluid-structure-sound interactions and control. Springer, Berlin, Heidelberg, pp 179–184Google Scholar
  3. 3.
    Zhang BF, Zhou Y, To S (2015) Unsteady flow structures around a high-drag Ahmed body. J Fluid Mech 777:291–326 (2015)CrossRefGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  1. 1.State Key Laboratory of Automotive Simulation and ControlJilin UniversityChangchunChina
  2. 2.Department of Mechanical EngineeringThe Hong Kong Polytechnic UniversityKowloonChina
  3. 3.Institute for Turbulence-Noise-Vibration Interaction and ControlShenzhen Graduate School, Harbin Institute of TechnologyShenzhenChina

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