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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2017, Vol. 38 ›› Issue (8): 120876-120876.doi: 10.7527/S1000-6893.2016.120876

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Introducing DMD method to study dynamic structures of flow separation with and without control

HONG Shuli1,2, HUANG Guoping1,2   

  1. 1. College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2. Jiangsu Province Key Laboratory of Aerospace Power System, Nanjing University of Aeronautics and Astronautics, Naning 210016, China
  • Received:2016-10-21 Revised:2016-11-18 Online:2017-08-15 Published:2017-01-11
  • Supported by:

    National Natural Science Foundation of China (51176072)

Abstract:

To analyze the mechanism of depressing flow separation with unsteady flow control technology, a numerical simulation for the experimental model of the divergent channel is carried out. Dynamic mode decomposition (DMD) technology is adopted to study the flow field of the curved divergent channel with and without pulsed jet control. With DMD technology, the complex flow field of the divergent channel containing spatial and temporal information can be decomposed hierarchically, and dynamical information as well as spatial coherent structure corresponding to the vortex can be captured and rendered. A comparison of the decomposed flow fields with and without control shows that with effective excitation, the coherent structure with the frequency approximating the frequency of the shedding vortex becomes more dominant in the initial flow field, and the overall flow field turns out be to more ordered. Some coherent structures, decomposed from flow field without control, are suppressed to make all modes more steady. The dominant structure of the controlled flow field has no obvious influence on the main flow.

Key words: flow separation, unsteady, flow control, coherent structure, dynamic mode decomposition (DMD)

CLC Number: