Chinese Journal of Theoretical and Applied Mechani ›› 2015, Vol. 47 ›› Issue (4): 571-579.DOI: 10.6052/0459-1879-14-381

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EFFECTS OF HIGH FREQUENCY BLOWING PERTURBATION ON A TURBULENT BOUNDARY LAYER

Wang Yanpin, Guo Hao, Liu Peiqing, Huang Qianmin   

  1. Institute of Fluid Mechanics, Beihang University, Beijing 100190, China
  • Received:2014-11-28 Revised:2015-05-19 Online:2015-07-23 Published:2015-06-01
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (11272034), the China-EU Aeronautical Science & Technology Cooperation Project MARS (MJ-F-2011-05) and Key Laboratory of Ministry of Water Resources of the Yellow River Sediment Research Fund Project.

Abstract:

An experimental study is conducted on a zero pressure gradient flat plate for investigating the effects of a periodical perturbation on the turbulent boundary layer over the flat plate. This experiment is focused on studying the effects of high frequency blowing on statistical characteristicss of near wall turbulence. By measuring and analyzing streamwise velocity signals at different streamwise locations with and without a periodical perturbation induced by a synthetic jet actuator, the conclusion of the experiment indicates skin friction reduction can be achieved downstream of the slot by applying high frequency periodical blowing perturbation. Owing to the intensity of the perturbation in the turbulent boundary layer is attenuating along the streamwise, the interaction between the perturbation and turbulent flow structures is attenuating. However, the negative spanwise vortexes induced by the high frequency perturbation are nearly of the same scale as the structures of bursting events, which directly impact the statistics of production and evolution of near wall coherent structures. As a result, the outcomes of bursting detection methods like VITA in the experiment show a contradictory phenomenon to the mechanism of skin friction reduction in low frequency blowing or steady blowing.

Key words:

high frequency blowing perturbation|turbulent boundary layer|skin friction reduction|synthetic jet

CLC Number: