Experimental investigation of shock wave oscillation on a thin supercritical airfoil

Document Type : Article


1 Faculty of New Sciences and Technologies, University of Tehran, Tehran, 1417614418, Iran

2 Department of Aerospace Engineering, Sharif University of Technology, Azadi Ave., Tehran, Zip Code: 1458889694, Iran


Experimental results of surface pressure distribution over a thin supercritical airfoil and its wake are presented. All tests were conducted at free stream Mach numbers from 0.27 to 0.85 and at different angles of attacks in a transonic wind tunnel. The model was equipped with static pressure orifices connected to high frequency pressure-transducers. The present paper evaluates variations of shock wave location with both Mach number and angle of attack variation as well as its interaction with the boundary layer leading to the buffet phenomenon. The frequency of the shock wave oscillation and unsteady wake behaviour at a freestream Mach no. of M=0.6 and at different angles of attacks are measured using cross-correlation technique by means of pressure sensors locating on the suction side of the model and via the rake total pressure data that was traversed vertically behind the model respectively. From the analysis of surface pressure distribution and wake data, drag divergence occurred at a certain angle of attack and at a frequency equal to the shock wave oscillation frequency.


Main Subjects

1. Humphreys, M.D., Pressure Pulsations on Rigid Airfoils at Transonic Speeds, NACA Research Memorandum L51I12, National Advisory Committee for Aeronautics (1951).
2. Gao, C., Zhang, W., and Ye, Z. "Reduction of transonic buffet onset for a wing with activated elasticity", Aerospace Science and Technology, 77, pp. 670-676 (2018).
3. Vos, R. and Farokhi, S. "Introduction to transonic aerodynamics", In Fluid Mechanics and Its Applications, 1st Edn, pp. XIII-555, Springer Netherlands, New York London (2015).
4. Lee, B.H.K. "Self-sustained shock oscillations on airfoils at transonic speeds", Progress in Aerospace Sciences, 37, pp. 147-196 (2001).
5. Liu, Y., Wang, G., Zhu, S., and Ye, Z. "Numerical study of transonic shock buffet instability mechanism", 46th AIAA Fluid Dynamics Conference, 13-17 June, Washington, D.C. (2016).
6. Szubert, D., Grossi, F., Garcia, A.J., Hoarau, Y., Hunt, J.C.R., and Braza, M. "Shock-vortex shear-layer interaction in the transonic  flow around a supercritical airfoil at high Reynolds number in buffet conditions", Journal of Fluids and Structures, 55, pp. 276-302 (2015).
7. Polentz, P.P., Page, W.A., and Levy, L.L., The Unsteady Normal Force Characteristics of Selected NACA Profiles at High Subsonic Mach Numbers, NACA Research Memorandum A55C02, National Advisory Committee for Aeronautics, May (1955).
8. Mabey, D.G., Some Remarks on Buffeting, Technical Memorandum Structures 980, Royal Aircraft Establishment, February (1981).
9. Sousa, R.S., Girardi, R.D., and Silva, R.G.A. "A new criterion for transonic buffeting onset estimation", 35th AIAA Applied Aerodynamics Conference, AIAA AVIATION Forum, AIAA 2017-4231 (2017).
10. Zhao, Z., Ren, X., Gao, C., Xiong, J., Liu, F., and Luo, S. "Experimental study of shock wave oscillation on SC (2)-0714 airfoil", 51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 07-10 January 2013, Grapevine (Dallas/Ft. Worth Region), Texas, AIAA 2013-0537. 
11. Fernie, R.M. and Babinsky, H. "Unsteady shock behaviour on a NACA 0012 aerofoil", 41st Aerospace Sciences Meeting and Exhibit, 6-9 January 2003, Reno, Nevada, AIAA 2003-226. 
12. Pearcey, H.H. "Some effects of shock-induced separation of turbulent boundary layers in transonic  flow past aerofoils", Aeronautical Research Council Reports and Memoranda, Reports and Memoranda No. 3I08 (1959).
13. Lee, B.H.K. "Effects of trailing-edge  flap on bffuet characteristics of a supercritical airfoil", J. Aircraft, 29(1), pp. 93-100 (1992).
14. Jacquin, L., Molton, P., Deck, S., Maury, B., and Soulevant, D. "Experimental study of shock oscillation over a transonic supercritical profile", AIAA, 47(9), pp. 1985-1994 (2009).
15. Tang, D. and Dowell, E.H. "Experimental aerodynamic response for an oscillating airfoil in buffeting  flow", Journal of AIAA, 52(6), pp. 1170-1179 (2014).
16. Kouchi, T., Yamaguchi, S., Koike, S., Nakajima, T., Sato, M., Kanda, H., and Yanase, S. "Wavelet analysis of transonic buffet on a two-dimensional airfoil with vortex generators", Exp Fluids, 57(11), pp. 57-166 (2016).
17. Liu, J. and Zhichung Yang, Z. "Numerical study on transonic shock oscillation suppression and buffet load alleviation for a supercritical airfoil using a microtab", Engineering Applications of Computational Fluid Mechanics, 10, pp. 529-544 (2016).
18. Tian, Y., Gao, S., Liu, P., and Wang, J. "Transonic bufflet control research with two types of shock control bump based on RAE2822 airfoil", Chinese Journal of Aeronautics, 30(5), pp. 1681-1696 (2017).
19. Gao, C., Zhang, W., and Ye, Z. "Numerical study on closed-loop control of transonic buffet suppression by trailing edge  ap", Computers & Fluids, 132, pp. 32- 45 (2016).
20. Golestani, A., Ehghaghi, M.B., and Soltani, M.R. "An experimental study of buffet detection on supercritical airfoils in transonic regime", Journal of Aerospace Engineering, 229(2), pp. 312-322 (2015).
21. Golestani, A., Soltani, M.R., and Masdari, M. "Effect of wind tunnel porosity on the  flow around an oscillating airfoil at transonic speed", Scientia Iranica, 24(3), pp. 1069-1076 (2017).
22. Amiri, K., Soltani, M.R., and Haghiri, A. "Steady flow quality assessment of a modified transonic wind tunnel", Scientia Iranica, 20(3), pp. 500-507 (2013).