Experimental investigation of shock wave oscillation on a thin supercritical airfoil

Document Type : Article

Authors

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

Abstract

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.

Keywords

Main Subjects


References
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
bu et 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 bu et 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
ow around a supercritical
airfoil at high Reynolds number in bu et 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
Pro les at High Subsonic Mach Numbers, NACA
Research Memorandum A55C02, National Advisory
Committee for Aeronautics, May (1955).
8. Mabey, D.G., Some Remarks on Bu eting, 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 bu eting 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 e ects of shock-induced separation
of turbulent boundary layers in transonic
ow past
aerofoils", Aeronautical Research Council Reports
and Memoranda, Reports and Memoranda No. 3I08
(1959).
13. Lee, B.H.K. E ects of trailing-edge
ap on bu et
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 pro le", AIAA, 47(9),
pp. 1985{1994 (2009).
15. Tang, D. and Dowell, E.H. Experimental aerodynamic
response for an oscillating airfoil in bu eting

ow", 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 bu et 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 bu et 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
bu et 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 bu et 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 bu et 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. E ect
of wind tunnel porosity on the
ow around an oscillating
airfoil at transonic speed", Scientia Iranica, 24(3),
pp. 1069{1076 (2017).
M. Masdari et al./Scientia Iranica, Transactions B: Mechanical Engineering 27 (2020) 795{805 805
22. Amiri, K., Soltani, M.R., and Haghiri, A. Steady flow quality assessment of a modi ed transonic wind
tunnel", Scientia Iranica, 20(3), pp. 500{507 (2013).