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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2014, Vol. 35 ›› Issue (4): 921-932.doi: 10.7527/S1000-6893.2013.0453

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Spatiotemporal Characteristics Analysis for Controlling Flow Separation in Divergent Curved Channels with POD Method

ZHU Jianfeng, HUANG Guoping, FU Xin, FU Yong   

  1. College of Energy & Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  • Received:2013-05-21 Revised:2013-11-05 Online:2014-04-25 Published:2013-11-26
  • Supported by:

    National Natural Science Foundation of China (51176072);Funding of Jiangsu Innovation Program for Graduate Education (CXLX11_0216)

Abstract:

In order to analyze the characteristic of a micro pulsed aspirated jet in a compressor, an experimental and numerical investigation is conducted about pulsed jet control, which is based on a divergent curved channels experimental mode. When the frequency of the pulsed jet is close to the characteristic frequency of the separation vortex, the control effects are obvious. In order to analyze the unsteady control mechanism, the proper orthogonal decomposition (POD) method is introduced, and the spatial and temporal flow characteristics are obtained. According to the POD analysis results of the steady and unsteady control methods, it can be noted that the main effect of the unsteady pulsed jet is reallocating the energy of each mode, and selectively strengthening or weakening certain modes; the effect of the steady jet is reducing in an overall manner the energy of high order modes. Based on the reasonable control parameters of the pulsed jet, the energy in higher modes will be transferred to the average flow mode, and the translation of modal energy comes from the reconstructing of spatial flow structurnd the ordering of modal evolution characteristics. Finally, experimental investigation is performed to validate the POD analysis. The results reflect partially the variation of spatiotemporal characteristics of a pulsed jet and the credibility of the POD analysis results is enhanced.

Key words: proper orthogonal decomposition, mode analysis, unsteadiness, flow separation, pulsed jet

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