中国物理B ›› 2019, Vol. 28 ›› Issue (5): 54701-054701.doi: 10.1088/1674-1056/28/5/054701

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Direct numerical simulation on relevance of fluctuating velocities and drag reduction in turbulent channel flow with spanwise space-dependent electromagnetic force

Dai-Wen Jiang(江代文), Hui Zhang(张辉), Bao-Chun Fan(范宝春), An-Hua Wang(王安华)   

  1. Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094, China
  • 收稿日期:2018-11-28 修回日期:2019-01-07 出版日期:2019-05-05 发布日期:2019-05-05
  • 通讯作者: Hui Zhang E-mail:zhanghui1902@hotmail.com
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 11672135) and a Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 201461).

Direct numerical simulation on relevance of fluctuating velocities and drag reduction in turbulent channel flow with spanwise space-dependent electromagnetic force

Dai-Wen Jiang(江代文), Hui Zhang(张辉), Bao-Chun Fan(范宝春), An-Hua Wang(王安华)   

  1. Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094, China
  • Received:2018-11-28 Revised:2019-01-07 Online:2019-05-05 Published:2019-05-05
  • Contact: Hui Zhang E-mail:zhanghui1902@hotmail.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 11672135) and a Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 201461).

摘要: Based on the Fourier-Chebyshev spectral method, the control of turbulent channel flow by space-dependent electromagnetic force and the mechanism of drag reduction are investigated with direct numerical simulation (DNS) methods for different Reynolds numbers. A formula is derived to express the relation between fluctuating velocities and the friction drag coefficient. With the application of electromagnetic force, the in-depth relations among the fluctuating velocities near the wall, Reynolds stress, and the effect of drag reduction for different Reynolds numbers are discussed. The results indicate that the maximum drag reductions can be obtained with an optimal combination of parameters for each case of different Reynolds numbers. The fluctuating velocities along the streamwise and normal directions are suppressed significantly, while the fluctuating velocity along the spanwise direction is enhanced dramatically due to the spanwise electromagnetic force. However, the values of Reynolds stress depend on the fluctuating velocities along the streamwise and normal directions rather than that along the spanwise direction. Therefore, the significant effect of drag reduction is obtained. Moreover, the maximum drag reduction is weakened due to the decay of control effect for fluctuating velocities as the Reynolds number increases.

关键词: flow control, turbulent channel flow, electromagnetic force, direct numerical simulation

Abstract: Based on the Fourier-Chebyshev spectral method, the control of turbulent channel flow by space-dependent electromagnetic force and the mechanism of drag reduction are investigated with direct numerical simulation (DNS) methods for different Reynolds numbers. A formula is derived to express the relation between fluctuating velocities and the friction drag coefficient. With the application of electromagnetic force, the in-depth relations among the fluctuating velocities near the wall, Reynolds stress, and the effect of drag reduction for different Reynolds numbers are discussed. The results indicate that the maximum drag reductions can be obtained with an optimal combination of parameters for each case of different Reynolds numbers. The fluctuating velocities along the streamwise and normal directions are suppressed significantly, while the fluctuating velocity along the spanwise direction is enhanced dramatically due to the spanwise electromagnetic force. However, the values of Reynolds stress depend on the fluctuating velocities along the streamwise and normal directions rather than that along the spanwise direction. Therefore, the significant effect of drag reduction is obtained. Moreover, the maximum drag reduction is weakened due to the decay of control effect for fluctuating velocities as the Reynolds number increases.

Key words: flow control, turbulent channel flow, electromagnetic force, direct numerical simulation

中图分类号:  (Flow control)

  • 47.85.L-
47.85.lb (Drag reduction)