中国物理B ›› 2017, Vol. 26 ›› Issue (8): 84704-084704.doi: 10.1088/1674-1056/26/8/084704

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

Mechanism of controlling turbulent channel flow with the effect of spanwise Lorentz force distribution

Yang Han(韩洋), Hui Zhang(张辉), Bao-Chun Fan(范宝春), Jian Li(李健), Dai-Wen Jiang(江代文), Zi-Jie Zhao(赵子杰)   

  1. Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094, China
  • 收稿日期:2017-03-24 修回日期:2017-04-13 出版日期:2017-08-05 发布日期:2017-08-05
  • 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 Nos. 11672135 and 11202102), the Fundamental Research Funds for the Central Universities, China (Grant No. 30916011347), and a Foundation for the Author of National Excellent Doctoral Dissertation, China (Grant No. 201461).

Mechanism of controlling turbulent channel flow with the effect of spanwise Lorentz force distribution

Yang Han(韩洋), Hui Zhang(张辉), Bao-Chun Fan(范宝春), Jian Li(李健), Dai-Wen Jiang(江代文), Zi-Jie Zhao(赵子杰)   

  1. Science and Technology on Transient Physics Laboratory, Nanjing University of Science and Technology, Nanjing 210094, China
  • Received:2017-03-24 Revised:2017-04-13 Online:2017-08-05 Published:2017-08-05
  • Contact: Hui Zhang E-mail:zhanghui1902@hotmail.com
  • About author:0.1088/1674-1056/26/8/
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11672135 and 11202102), the Fundamental Research Funds for the Central Universities, China (Grant No. 30916011347), and a Foundation for the Author of National Excellent Doctoral Dissertation, China (Grant No. 201461).

摘要:

A direct numerical simulation (DNS) is performed to investigate the control effect and mechanism of turbulent channel flow with the distribution of spanwise Lorentz force. A sinusoidal distribution of constant spanwise Lorentz force is selected, of which the control effects, such as flow characters, mean Reynolds stress, and drag reductions, at different parameters of amplitude A and wave number kx are discussed. The results indicate that the control effects vary with the parameter A and kx. With the increase of A, the drag reduction rate Dr first increases and then decreases rapidly at low kx, and slowly at high kx. The low drag reduction (or even drag increase) is due to a weak suppression or even the enhancements of the random velocity fluctuation and mean Reynolds stress. The efficient drag reduction is due to the quasi-streamwise vortex structure induced by Lorentz force, which contributes to suppressing the random velocity fluctuation and mean Reynolds stress, and the negative vorticity improves the distribution of streamwise velocity. Therefore, the optimal control effect with a drag reduction of up to 58% can be obtained.

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

Abstract:

A direct numerical simulation (DNS) is performed to investigate the control effect and mechanism of turbulent channel flow with the distribution of spanwise Lorentz force. A sinusoidal distribution of constant spanwise Lorentz force is selected, of which the control effects, such as flow characters, mean Reynolds stress, and drag reductions, at different parameters of amplitude A and wave number kx are discussed. The results indicate that the control effects vary with the parameter A and kx. With the increase of A, the drag reduction rate Dr first increases and then decreases rapidly at low kx, and slowly at high kx. The low drag reduction (or even drag increase) is due to a weak suppression or even the enhancements of the random velocity fluctuation and mean Reynolds stress. The efficient drag reduction is due to the quasi-streamwise vortex structure induced by Lorentz force, which contributes to suppressing the random velocity fluctuation and mean Reynolds stress, and the negative vorticity improves the distribution of streamwise velocity. Therefore, the optimal control effect with a drag reduction of up to 58% can be obtained.

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

中图分类号:  (Flow control)

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