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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (2): 545-554.doi: 10.7527/S1000-6893.2015.0192

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Experiment research of active flow control of turbulent separated flow on backward-facing step using synthetic jet perturbation

LI Binbin1, YAO Yong1, JIANG Yubiao2, HUANG Yong2, GU Yunsong3, CHENG Keming3   

  1. 1. School of Civil Engineering and Architechture, Southwest University of Science and Technology, Mianyang 621010, China;
    2. Low Speed Aerodynamics Research Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China;
    3. College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2015-01-30 Revised:2015-07-01 Online:2016-02-15 Published:2015-08-31
  • Supported by:

    State Key Laboratory Fund of Aerodynamics(JBKY14010201)

Abstract:

Backward-facing step flow is typical in the research of fluid mechanics and it mainly investigates the sudden expansion of cross-sectional flow around a bluff body. Backward-facing step flow separation will lead to some adverse effects, such as high-speed vortex formation, flow losses, pressure pulsation and aerodynamic noise. Experimental investigation on separated reattachment flow control of two-dimensional backward-facing step turbulence with synthetic jet arrays is conducted. The unsteady flow field structure of a backward-facing step and surface pressure distribution are measured with seven-hole probes particle image velocimetry(PIV), hot wire anemometer, and pressure transducers as well. The results show that the perturbation of synthetic jet which is formed at the upper edge of the step can effectively decrease the non-dimensional length of reattachment flow by about 25% at most, and synthetic jet control increases the turbulent kinetic energy and Reynolds stress along the downstream steps and enhances the mixing efficiency of the flow field. The hot wire results show that frequency is a key parameter of backward facing step flow separation control; when the disturbance frequency is 260 Hz, the ratio of disturbance frequency to shear layer vortex shedding frequency is 1.32,the synthetic jet control can be applied to enhancing the energy of separated shear layer at a half of disturbance frequency and the flow control can be achieved only with low consumption of energy.

Key words: backward-facing step, synthetic jet, active flow control, reattachment length, turbulent flow

CLC Number: