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Turbulent Ramp Flow Control Using Unsteady Blowing Upstream of the Separation Point

  • P. Sujar-Garrido
  • J. C. Hao
  • Y. Zhou
Conference paper
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

The control of a two-dimensional turbulent flow separation from a 25°—backward-facing-ramp is experimentally studied using an unsteady upstream blowing through a spanwise slit with a view to reducing the recirculation length. The Reynolds number examined is 9.38 × 104, based on the ramp height h. Three control parameters are examined, i.e. the blowing amplitude, frequency and duty cycle. Extensive measurements of the flow are carried out using PIV, pressure and hotwire techniques. The results are compared with those of the natural flow and under unsteady blowing. The time-averaged recirculation bubble is found to contract in length by 40% under the optimum control parameters, which correspond to a very small fraction of input energy. It is further found that the optimization control frequency is close to the shedding frequency of the uncontrolled shear layer captured at 1 h downstream of the separation point.

Keywords

Flow control Backward-facing ramp Unsteady blowing actuation 

Notes

Acknowledgements

The financial support given from Shenzhen Government through grant JCYJ20150625142543469 is gratefully acknowledged.

References

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Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  1. 1.State Key Laboratory of AerodynamicsChina Aerodynamics Research and Development CenterMianyang SichuanChina
  2. 2.Institute for Turbulence-Noise-Vibration Interactions and ControlShenzhen Graduate School Harbin Institute of Technology, Xili University TownShenzhenChina

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