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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (11): 526806.doi: 10.7527/S1000-6893.2022.26806

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Numerical study on impact of shock control bump on transonic buffet

ZHANG Shenghua1, DENG Feng1, QIN Ning2, LIU Xueqiang1   

  1. 1. National Defense Key Laboratory of Advanced Aircraft Design Technology, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2. Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3 JD, United Kingdom
  • Received:2021-12-10 Revised:2022-01-04 Online:2022-11-15 Published:2022-02-17
  • Supported by:
    National Natural Science Foundation of China (12032011,11502112,11672132); A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions

Abstract: The Shock wave Control Bump (SCB) can effectively weaken the shock wave intensity of the airfoil at transonic speeds, meanwhile exerting a positive effect on transonic buffet control. In this study, the URANS method is applied to numerical simulation to explore the control effect of the 2D SCB on the OAT15A supercritical airfoil under the transonic buffet condition. The differences between the two goals of drag reduction and buffet control are further investigated. Two bumps are designed with drag reduction optimization at cruise design points. Under the buffet condition, the bumps delayed the pressure recovery on the upper surface of the airfoil and weakened the interaction between the shock wave and the boundary layer. Therefore, the pressure fluctuation amplitude of bump configurations is reduced despite incomplete suppression of the buffet. Then, the effect of the bump crest position, height and length on the buffet is studied. The working mechanism of the SCB to suppress the buffet is obtained by analyzing the typical flow field. The bump reduced the shock wave intensity, preventing the boundary layer at the rear of the bump from moving upstream and interfering with the shock wave, resulting in shock buffet suppression. Based on the drag reduction design at the cruise design point, the relative reference positions of the two bumps are 0.04c and 0.10c (c representing length of the chord), respectively. The position range of the bumps at the same height to completely suppress the buffet without reducing the lift are[-0.01, 0.02]c and[0.01, 0.08]c, respectively. The smallest variation of the bump location between drag reduction and shock buffet control is 0.02c, and this distance has a significant impact on cruise characteristics and buffet performance of the airfoil. Consequently, the two types of bumps designed based on drag reduction at the cruise points and buffet control under the buffet condition have different crest positions. In engineering design, a trade-off between the two design goals should be achieved in bump design by comprehensive consideration to improve the overall performance of airfoils under transonic flight conditions.

Key words: shock control bump, supercritical airfoil, transonic buffet, URANS, flow control

CLC Number: