Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T22:33:38.939Z Has data issue: false hasContentIssue false
  • English
  • Français

Trailing-edge flap flow control for dynamic stall

Published online by Cambridge University Press:  27 January 2016

R. B. Green ,
E. A. Gillies  and
Y. Wang
R. B. Green*
Affiliation:
Department of Aerospace Engineering, University of Glasgow, Glasgow, UK
*
richard.green@glasgow.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

Results of a series of oscillatory dynamic stall tests of a rotor aerofoil fitted with a pulsed, trailing-edge flap are presented. Flap deflection amplitude, motion profile, duration and starting phase were investigated to assess the potential of the flap for mitigating the adverse effects of dynamic stall, which is one of the limiting factors for rotor blades on the retreating side of a helicopter rotor. The tests were a continuation of the investigations by Ref. 1 who used a computational fluid dynamics method on a symmetric NACA section, and our results broadly confirm their conclusions by experimental test, using a modern rotor section. The results presented in this paper also confirm the observations from experimental work by Refs 2 and 3, which were undertaken at lower Reynolds number and with a larger flap. In the present study, the flap mitigates the high negative pitching moment and negative pitch damping seen in dynamic stall by strong suction being generated over the aerofoil lower surface, and it is the modification to the lower surface shape by the flap that creates this effect. The dynamic stall vortex acts to enhance the lower surface suction, and careful flap phasing and flap motion profile shaping can make the control more effective.

Type
Research Article
Information
The Aeronautical Journal , Volume 115 , Issue 1170 , August 2011 , pp. 493 - 503
Copyright
Copyright © Royal Aeronautical Society 2011 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Feszty, D., Gillies, E.A. and Vezza, M. Alleviation of airfoil dynamic stall moments via trailing-edge-flap flow control, AIAA J, 2004, 42, (1), pp 17–25.Google Scholar
2. Gerontakos, P. and Lee, T. Dynamic stall flow control via a trailing-edge flap, AIAA J, 2006, 44, (3), pp 469–480.Google Scholar
3. Lee, T. and Gerontakos, P. Effect of flap motion on unsteady aerodynamic loads, J Aircr, 2007, 44, (1), pp 334–338.Google Scholar
4. McCroskey, W.J. Unsteady airfoils, Annual Review of Fluid Mechanics, 1982, 14, pp 185–311.Google Scholar
5. Carr, L.W., McAlister, K.W. and McCroskey, W.J. Analysis of the development of dynamic stall based on oscillating airfoil experiments. NASA TN D-8382, 1977.Google Scholar
6. Doligalski, T.L., Smith, C.R. and Walker, J.D.A. Vortex interactions with walls, Annual Review of Fluid Mechanics, 1994, 26, pp 573–616.Google Scholar
7. Shih, C., Lourenco, L.M. and Krothapalli, A. Investigation of flow at leading and trailing-edges of pitching-up airfoil, AIAA J, 1995, 33, (8), pp 1369–1376.Google Scholar
8. Chandrasekhara, M.S., Wilder, M.C. and Carr, L.W. Compressible dynamic stall control: comparison of two approaches, J Aircr, 2001, 38, (3), pp 448–453.Google Scholar
9. Yu, Y.H., Lee, S., McAlister, K.W., Tung, C. and Wang, C.M. Dynamic stall control for advanced rotorcraft application, AIAA J, 1995, 33, (2), pp 289–295.Google Scholar
10. Nguyen, K. Active control of helicopter blade stall, J Aircr, 1998, 35, (1), pp 91–98.Google Scholar
11. Carta, F.O. An analysis of the stall flutter instability of helicopter rotor blades, J American Helicopter Society, 1967, 12, (4), pp 1–18.Google Scholar
12. Panda, J. and Zaman, K.B.M.Q. Experimental investigation of the flow field of an oscillating airfoil and estimation of lift from wake surveys. J Fluid Mechanics, 1994, (265), pp 65–95.Google Scholar