Micro-blowing: Effect on flow characteristics in turbulent flat plate boundary layer and drag reduction mechanism

被引：0
|
作者：
Fan Y. [1 ]
Zhang Y. [1 ]
Ye Z. [1 ]
Zou J. [1 ]
Zheng Y. [1 ]
机构：
[1] School of Aeronautics and Astronautics, Zhejiang University, Hangzhou
来源：
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | 2020年 / 41卷 / 10期
关键词：
Drag reduction; Intensity of turbulence; Micro-blowing technology; Turbulent structure; Vorticity;
D O I：
10.7527/S1000-6893.2020.23814
中图分类号：
学科分类号：
摘要：
Micro-blowing technology can change the turbulent structure in a flat plate flow and reduce the wall friction drag. In this paper, two cases of inflow through a smooth plate and a NASA-PN2 porous plate at Mach number 0.7 are respectively resolved by direct numerical simulation. Comparison of the flow characteristics in the two cases proves the effectiveness of micro-blowing technology on drag reduction, with the maximum rate reaching 45%. Furthermore, because of the "memory" function controlled by micro-blowing, the effect will last for a certain distance in the downstream, thus expanding the area of drag reduction. The explanation for the drag reduction in a wall turbulent boundary layer is the production of a low-speed "turbulence spot" in the near-wall region, which increases the thickness of viscous sub-layer and uplifts the average velocity profile. However, the turbulent velocity fluctuations in the boundary layer are strengthened simultaneously. Further analysis of the evolution of stream-wise vortex fluctuations reveals that micro-blowing plays multiple roles. It not only enhances the intensity of stream-wise vortex fluctuations, but also uplifts the stream-wise vortex clusters away from the wall, hence directly reducing the interaction between the stream-wise vortex and the wall surface. In addition, the impact caused by micro-blowing will leave dents on the vortex surface, leading to more dispersed and finely broken vortex clusters. © 2020, Beihang University Aerospace Knowledge Press. All right reserved.
引用
收藏
相关论文
共 30 条
  • [1] KORNILOV V I, BOIKO A V., Efficiency of air microblowing through microperforated wall for flat plate drag reduction, AIAA Journal, 50, 3, pp. 724-732, (2012)
  • [2] LARDEAU S, LESCHZINER M A., The streamwise drag-reduction response of a boundary layer subjected to a sudden imposition of transverse oscillatory wall motion, Physics of Fluids, 25, 7, (2013)
  • [3] DU Y, KARNIADAKIS G E., Suppressing wall turbulence by means of a transverse traveling wave, Science, 288, 5469, pp. 1230-1234, (2000)
  • [4] CUI G, PAN C, WU D, Et al., Effect of drag reducing riblet surface on coherent structure in turbulent boundary layer, Chinese Journal of Aeronautics, 32, 11, pp. 2433-2442, (2019)
  • [5] MARTELL M B, ROTHSTEIN J P, PEROT J B., An analysis of superhydrophobic turbulent drag reduction mechanisms using direct numerical simulation, Physics of Fluids, 22, 6, (2010)
  • [6] HWANG D P, BIESIADNY T., Experimental evaluation of penalty associated with micro-blowing for reducing skin friction, 36th AIAA Aerospace Sciences Meeting and Exhibit, (1997)
  • [7] TILLMAN T, HWANG D., Drag reduction on a large-scale nacelle using a micro-blowing technique, 37th Aerospace Sciences Meeting and Exhibit, (1999)
  • [8] KAMETANI Y, KOTAKE A, FUKAGATA K, Et al., Drag reduction capability of uniform blowing in supersonic wall-bounded turbulent flows, Physical Review Fluids, 2, 12, (2017)
  • [9] KIM K, SUNG H J., Effects of unsteady blowing through a spanwise slot on a turbulent boundary layer, Journal of Fluid Mechanics, 557, pp. 423-450, (2006)
  • [10] HWANG D., Review of research into the concept of the microblowing technique for turbulent skin friction reduction, Progress in Aerospace Sciences, 40, 8, pp. 559-575, (2004)
123