中国物理B ›› 2024, Vol. 33 ›› Issue (7): 74701-074701.doi: 10.1088/1674-1056/ad3dc7

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Experimental investigation of closed-loop active control to modulate coherent structures by mu-level method

Jian-Xia Bai(白建侠)1, Zi-Ye Fan(范子椰)2, Nan Jiang(姜楠)2,4,†, Qiu-Ying Li(李秋营)1, and Xiao-Bo Zheng(郑小波)3   

  1. 1 Department of Mathematics, Tianjin Renai College, Tianjin 301636, China;
    2 Institute of Mechanics, Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300354, China;
    3 College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
    4 Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin 300354, China
  • 收稿日期:2023-12-19 修回日期:2024-02-26 接受日期:2024-04-12 出版日期:2024-06-18 发布日期:2024-06-18
  • 通讯作者: Nan Jiang E-mail:nanj@tju.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12202309, 1233000165, 12172242, and 12272265), Science and Technology Program of Gansu Province of China (Grant No. 22JR5RA304), and Tianjin Research Innovation for Postgraduate Students (Grant No. 22KJ049).

Experimental investigation of closed-loop active control to modulate coherent structures by mu-level method

Jian-Xia Bai(白建侠)1, Zi-Ye Fan(范子椰)2, Nan Jiang(姜楠)2,4,†, Qiu-Ying Li(李秋营)1, and Xiao-Bo Zheng(郑小波)3   

  1. 1 Department of Mathematics, Tianjin Renai College, Tianjin 301636, China;
    2 Institute of Mechanics, Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300354, China;
    3 College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China;
    4 Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin 300354, China
  • Received:2023-12-19 Revised:2024-02-26 Accepted:2024-04-12 Online:2024-06-18 Published:2024-06-18
  • Contact: Nan Jiang E-mail:nanj@tju.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12202309, 1233000165, 12172242, and 12272265), Science and Technology Program of Gansu Province of China (Grant No. 22JR5RA304), and Tianjin Research Innovation for Postgraduate Students (Grant No. 22KJ049).

摘要: The experimental research on zero-net-mass-flux jet closed-loop active control was conducted in the wind tunnel. The mu-level method successfully detected burst events of the coherent structures. The streamwise velocity signals in the turbulent boundary layer were measured by HWA. The drag reduction rate of 16.7% is obtained comparable to that of the open-loop control and saves 75% of the input energy at the asynchronous 100 V/160 Hz control case, which reflects the advantages of the closed-loop control. The experimental findings indicate that the intensity increases in the near-wall region. The perturbation of the PZT vibrators on the skewness factor is concentrated in the region $y^{+}<60$. The generation of high-speed fluids is depressed and the downward effect of high-speed fluids weakens. The alteration of energy distribution and the discernible impact of modulation between structures of varying scales are observed. The correlation coefficient exhibits a strong positive correlation, which indicates that the large-scale structures produce modulation effect on small-scale ones. The occurrence of burst events is effectively suppressed. The disturbance has the characteristics of stable periodicity, positive and negative symmetry, low intermittency, and high pulsation strength. The conditional phase waveform shows that the fluctuation amplitude increases, indicating amplitude modulation effects on coherent structures.

关键词: turbulent boundary layer (TBL), burst event, coherent structures, mu-level method

Abstract: The experimental research on zero-net-mass-flux jet closed-loop active control was conducted in the wind tunnel. The mu-level method successfully detected burst events of the coherent structures. The streamwise velocity signals in the turbulent boundary layer were measured by HWA. The drag reduction rate of 16.7% is obtained comparable to that of the open-loop control and saves 75% of the input energy at the asynchronous 100 V/160 Hz control case, which reflects the advantages of the closed-loop control. The experimental findings indicate that the intensity increases in the near-wall region. The perturbation of the PZT vibrators on the skewness factor is concentrated in the region $y^{+}<60$. The generation of high-speed fluids is depressed and the downward effect of high-speed fluids weakens. The alteration of energy distribution and the discernible impact of modulation between structures of varying scales are observed. The correlation coefficient exhibits a strong positive correlation, which indicates that the large-scale structures produce modulation effect on small-scale ones. The occurrence of burst events is effectively suppressed. The disturbance has the characteristics of stable periodicity, positive and negative symmetry, low intermittency, and high pulsation strength. The conditional phase waveform shows that the fluctuation amplitude increases, indicating amplitude modulation effects on coherent structures.

Key words: turbulent boundary layer (TBL), burst event, coherent structures, mu-level method

中图分类号:  (Drag reduction)

  • 47.85.lb
47.85.ld (Boundary layer control) 47.27.nb (Boundary layer turbulence ?) 47.27.De (Coherent structures)