Skip to main content

Advertisement

SpringerLink
Log in

Reduction of dynamic stall using a back-flow flap

  • Original Paper
  • Published:
CEAS Aeronautical Journal Aims and scope Submit manuscript

Abstract

A back-flow flap attached to the suction side of an airfoil is investigated in both passively and actively actuated modes for the control of dynamic stall. This method of dynamic stall control has low power requirements and no parasitic drag when not actuated. Experiments in a low-speed wind tunnel at 50 m/s were used to characterize the reduction in dynamic stall hysteresis using pressure measurements on the midline airfoil section. It was found that the pitching moment peak is reduced by an average of 25% for all deep stall test cases for active actuation of the flap, while for passive actuation the pitching moment peak is reduced by 19%. In each case the maximum lift remained the same, while the peak drag increased by an average of 2.5% for the active flap, and by 0.9% for the passive flap. With the flap closed at low angles of attack, the reference values of the airfoil are retained.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20
Fig. 21
Fig. 22
Fig. 23
Fig. 24
Fig. 25
Fig. 26

Similar content being viewed by others

Abbreviations

\(\alpha ; \alpha _\mathrm{max}\) :

Angle of attack; maximum (\(^\circ\))

c :

Airfoil model chord (m)

\(C_\mathrm{D}; C_{\mathrm{D}_\mathrm{max}}\) :

Drag coefficient; peak

\(C_\mathrm{L}; C_{\mathrm{L}_\mathrm{max}}\) :

Lift coefficient; peak

\(C_\mathrm{M}; C_{\mathrm{M}_\mathrm{min}}\) :

Pitching moment coefficient; peak

\(C_\mathrm{P}\) :

Pressure coefficient

f :

Frequency of pitching (Hz)

M :

Mach number

k :

Reduced frequency: \(k=\pi fc/v_{\infty }\)

Re :

Reynolds number based on c

t :

Time (s)

T :

Period (s)

u, v :

Velocity: in x direction, in z direction (m/s)

\(v_{\infty }\) :

Freestream velocity (m/s)

x, z :

Coordinates: chord, upward (m)

References

  1. Carr, L.W.: Progress in the analysis and prediction of dynamic stall. J. Aircr. 25(1), 6–17 (1988). doi:10.2514/3.45534

    Article  Google Scholar 

  2. Leishman, J.G.: Dynamic stall experiments on the NACA 23012 aerofoil. Exp. Fluids 9(1–2), 49–58 (1990). doi:10.1007/BF00575335

    Article  Google Scholar 

  3. Chandrasekhara, M.S., Wilder, M.C., Carr, L.W.: Competing mechanisms of compressible dynamic stall. AIAA J. 36(3), 387–393 (1998). doi:10.2514/2.375

    Article  Google Scholar 

  4. Greenblatt, D., Wygnanski, I.: Dynamic stall control by periodic excitation, part 1: NACA 0015 parametric study. J. Aircr. 38(3), 430–438 (2001). doi:10.2514/2.2810

    Article  Google Scholar 

  5. Greenblatt, D., Nishri, B., Darabi, A., Wygnanski, I.: Dynamic stall control by periodic excitation, part 2: mechanisms. J. Aircr. 38(3), 439–447 (2001). doi:10.2514/2.2811

    Article  Google Scholar 

  6. Gardner, A.D., Richter, K., Mai, H., Neuhaus, D.: Experimental investigation of high-pressure pulsed blowing for dynamic stall control. CEAS Aeronaut. J. 5(2), 185–198 (2014). doi:10.1007/s13272-014-0099-y

    Article  Google Scholar 

  7. Post, M.L., Corke, T.C.: Separation control using plasma actuators: dynamic stall vortex control on oscillating airfoil. AIAA J. 44(12), 3125–3135 (2006). doi:10.2514/1.22716

    Article  Google Scholar 

  8. Matalanis, C.G., Min, B.Y., Bowles, P.O., Jee, S., Wake, B.E., Crittenden, T.M., Woo, G., Glezer, A.: Combustion-powered actuation for dynamic-stall suppression: high-mach simulations and low-mach experiments. AIAA J. 53(8), 2151–2163 (2015). doi:10.2514/1.J053641

    Article  Google Scholar 

  9. Freymuth, P., Jackson, S., Bank, W.: Toward dynamic separation without dynamic stall. Exp. Fluids 7(3), 187–196 (1989)

    Article  Google Scholar 

  10. McCloud, K.L., Hall, L.P., Brady, J.A.: Full-scale wind tunnel tests of blowing boundary layer control applied to a helicopter rotor. NASA TN D-335 (1960)

  11. Weaver, D., McAlister, K.W., Tso, J.: Control of VR7 dynamic stall by strong steady blowing. J. Aircr. 41(6), 1404–1413 (2004). doi:10.2514/1.4413684-686

    Article  Google Scholar 

  12. Gardner, A.D., Richter, K., Mai, H., Neuhaus, D.: Experimental investigation of air jets for the control of compressible dynamic stall. J. Am. Helicopter Soc. 58(4), 1–14 (2013). doi:10.4050/JAHS.58.042001

    Article  Google Scholar 

  13. Martin, P., Wilson, J., Berry, J., Wong, T., Moulton, M., McVeigh, M.: Passive control of compressible dynamic stall. In: Paper 2008–7506, 26th AIAA Applied Aerodynamics Conference, pp 18–21, Honolulu. Hawaii, USA (2008). doi:10.2514/6.2008-7506

  14. Mai, H., Dietz, G., Geissler, W., Richter, K., Bosbach, J., Richard, H., de Groot, K.: Dynamic stall control by leading edge vortex generators. J. Am. Helicopter Soc. 53(1), 26–36 (2008). doi:10.4050/JAHS.53.26

    Article  Google Scholar 

  15. Heine, B., Mulleners, K., Joubert, G., Raffel, M.: Dynamic stall control by passive disturbance generators. AIAA J. 51(9), 2086–2097 (2013). doi:10.2514/1.J051525

    Article  Google Scholar 

  16. Prince, S.A., Khodagolian, V., Singh, C.: Aerodynamic stall suppression on airfoil sections using passive air-jet vortex generators. AIAA J. 47(9), 2232–2242 (2009). doi:10.2514/1.41986

    Article  Google Scholar 

  17. McAlister, K.W., Tung, C.: Suppression of dynamic stall with a leading-edge slat. NASA technical paper 3357. ATCOM Technical Report 92-A-013 (1993)

  18. Le Pape, A., Costes, M., Richez, F., Joubert, G., David, F., Deluc, J.M.: Dynamic stall control using deployable leading-edge vortex generators. AIAA J. 50(10), 2135–2145 (2012). doi:10.2514/1.J051452

    Article  Google Scholar 

  19. Joubert, G., Le Pape, A., Heine, B., Huberson, S.: Investigation of dynamic stall control by deployable vortex generator using time-resolved PIV analysis and URANS computations. AIAA J. 51(1), 240–252 (2013). doi:10.2514/1.J051767

    Article  Google Scholar 

  20. Chandrasekhara, M.S., Wilder, M.C., Carr, L.W.: Unsteady stall control using dynamically deforming airfoils. AIAA J. 36(10), 1792–1800 (1998)

    Article  Google Scholar 

  21. Martin, P.B., McAlister, K.W., Chandrasekhara, M.S., Geissler, W.: Dynamic stall measurements and computations for a VR-12 airfoil with a variable droop leading edge. American Helicopter Society 59th annual forum, Alexandria (2003)

  22. Gerontakos, P., Lee, T.: Dynamic stall flow control via a trailing-edge flap. AIAA J. 44(3), 469–480 (2006). doi:10.2514/1.17263

    Article  Google Scholar 

  23. Rennie, R., Jumper, E.J.: Experimental measurements of dynamic control surface effectiveness. J. Aircr. 33(5), 880–887 (1996)

    Article  Google Scholar 

  24. Ekaterinaris, J.A.: Numerical investigations of dynamic stall active control for incompressible and compressible flows. J. Aircr. 39(1), 71–78 (2002)

    Article  Google Scholar 

  25. Ekaterinaris, J.A.: Prediction of active flow control performance on airfoils and wings. Aerosp. Sci. Technol. 8(5), 401–410 (2004)

    Article  MATH  Google Scholar 

  26. Kinzel, M.P., Maughmer, M.D., Lesieutre, G.A.: Miniature trailing-edge effectors for rotorcraft performance enhancement. J. Am. Helicopter Soc. 52(2), 146–158 (2007)

    Article  Google Scholar 

  27. Pastrikakis, V.A., Steijl, R., Barakos, G.N.: Effect of active gurney flaps on overall helicopter flight envelope. Aeronaut. J. 120(1230), 1230–1261 (2016). doi:10.1017/aer.2016.57

    Article  Google Scholar 

  28. Bechert, D.W., Bruse, M., Hage, W., Meyer, R.: Biological surfaces and their application: laboratory and flight experiments on drag reduction and separation control. AIAA Paper, 97-1960 (1997)

  29. Patone G., Müller, W.: Aeroflexible Oberflächenklappen als Rückstrombremsen nach dem Vorbild der Deckfedern des Vogelflügels, Engl: Aeroflexible surface flaps as reverse-flow brakes, modelled after the pop-up feathers of a bird. TR-96-05, TU Berlin (1996)

  30. Meyer, R.K.J.: Experimentelle Untersuchungen von Rückstromklappen auf Tragflügeln zur Beeinflussung von Strömungsablösungen, Engl: Experimental investigation of back-flow flaps on wings for the control of flow separation. Doctoral thesis, TU Berlin, Mensch-und-Buch-Verlag (2000). ISBN 3-89820-205-4

  31. Schatz, M., Knacke, T., Thiele, F., Meyer, R., Hage, W., Bechert, D.W.: Separation control by self-activated movable flaps. In: 42nd AIAA Aerospace Sciences Meeting. AIAA-2004-1243 (2004)

  32. Kernstine, K.H., Moore, C.J., Cutler, A., Mittal, R.: Initial characterization of self-activated movable flaps, ’pop-up feathers’. AIAA 2008-369. 46th AIAA Aerospace Sciences Meeting and Exhibit, 7–10 January 2008, Reno, Nevada

  33. Bramesfeld, G., Maughmer, M.D.: Experimental investigation of self-actuating, upper-surface, high-lift-enhancing effectors. J. Aircr. 39(1), 120–124 (2002). doi:10.2514/2.2905

    Article  Google Scholar 

  34. Brücker, C., Weidner, C.: Separation control via self-adaptive hairy flaplet arrays. In: ERCOFTAC International Symposium—Unsteady Separation in Fluid-Structure Interaction, Mykonos, Greece, June 17–21 (2013)

  35. Höfinger, M.: Rotorblatt mit integrierter passiver Oberflächenklappe. Engl: Rotor blade with integrated passive surface flap. German Patent DE 10 2010 041 111 A1, 22.03.2012

  36. Kaufmann, K., Gardner, A.D., Richter, K.: Numerical investigations of a back-flow flap for dynamic stall control. In: New Results in Numerical and Experimental Fluid Mechanics IX, Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol. 124, pp. 255–262 (2014). doi:10.1007/978-3-319-03158-3_26

  37. Opitz, S., Gardner, A.D., Kaufmann, K.: Aerodynamic and structural investigation of an active back-flow flap for dynamic stall control. CEAS Aeronaut. J. 5(3), 279–291 (2014). doi:10.1007/s13272-014-0106-3

    Article  Google Scholar 

  38. Opitz, S., Kaufmann, K., Gardner, A.D.: An active back-flow flap for a helicopter rotor blade. Adv. Aircr. Spacecr. Sci. 1(1), 69–91 (2014). doi:10.12989/aas.2014.1.1.069

    Article  Google Scholar 

  39. McCroskey, W.J., Pucci, S.L.: Viscous–inviscid interaction on oscillating airfoils in subsonic flow. AIAA J. 20(2), 167–174 (1982)

    Article  Google Scholar 

  40. Greenblatt, D., Wygnanski, I.: Effect of leading edge curvature on airfoil separation control. J. Aircr. 40(3), 473–481 (2003). doi:10.2514/2.3142

    Article  Google Scholar 

  41. Ruotolo, A., Meseguer Ruiz, J.: A low cost, low speed wind tunnel for dynamic stall measurement. In: European Wind Energy Conference, Warsaw, Poland, pp. 20–23 (2010)

  42. Schatzman, D.M.: A study of unsteady turbulent boundary layer separation under conditions relevant to helicopter aerodynamics. PhD Thesis, University of Notre Dame (2011)

  43. Zanotti, A., Gibertini, G.: Experimental investigation of the dynamic stall phenomenon on a NACA 23012 oscillating airfoil. In: Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering (2012). doi:10.1177/0954410012454100

  44. Fugelsang, P., Antoniou, I., Sørensen, N.N., Madsen, H.A.: Validation of a wind tunnel testing facility for blade surface pressure measurements. Risø National Laboratory Report, Risø-R-981(EN), Denmark (1998)

  45. Raffel, M., Kompenhans, J., Wernert, P.: Investigation of the unsteady flow velocity field above an airfoil pitching under deep dynamic stall conditions. Exp. Fluids 19(2), 103–111 (1995). doi:10.1007/BF00193856

    Article  Google Scholar 

  46. Bowles, P.O.: Wind tunnel experiments on the effect of compressibility on the attributes of dynamic stall. PhD Thesis, Notre Dame (2012)

  47. Carr, L.W., Chandrasekhara, M.S.: Compressibility effects on dynamic stall. Progr. Aerosp. Sci. 32(6), 523–573 (1996)

    Article  Google Scholar 

  48. Ekaterinaris, J.A., Platzer, M.F.: Computational prediction of airfoil dynamic stall. Progr. Aerosp. Sci. 33(11–12), 759–846 (1998)

    Article  Google Scholar 

  49. Leishman, G.J.: Principles of Helicopter Aerodynamics, vol. 2. Cambridge University Press, Cambridge (2006). (ISBN:978-0521858601)

    Google Scholar 

  50. Richter, K., Le Pape, A., Knopp, T., Costes, M., Gleize, V., Gardner, A.D.: Improved two-dimensional dynamic stall prediction with structured and hybrid numerical methods. J. Am. Helicopter Soc. 56(4), 1–12 (2011). doi:10.4050/JAHS.56.042007

    Article  Google Scholar 

  51. Spentzos, A., Barakos, G.N., Badcock, K.J., Richards, B.E., Wernert, P., Schreck, S., Raffel, M.: Investigation of three-dimensional dynamic stall using computational fluid dynamics. AIAA J. 43, 1023–1033 (2005)

    Article  Google Scholar 

  52. Gardner, A.D., Richter, K., Rosemann, H.: Numerical investigation of air jets for dynamic stall control on the OA209 airfoil. CEAS Aeronaut. J. 1(1), 1–4 (2011). doi:10.1007/s13272-011-0002-z

    Google Scholar 

Download references

Acknowledgements

We would like to thank our colleague Kurt Kaufman for valuable discussions and Markus Krebs for his support during the wind tunnel experiment.

Author information

Authors and Affiliations

  1. DLR Institute of Aerodynamics and Flow Technology, Bunsenstrasse 10, 37073, Göttingen, Germany

    A. D. Gardner, C. C. Wolf & C. B. Merz

  2. Institute of Composite Structures and Adaptive Systems, Lilienthalplatz 7, 38108, Braunschweig, Germany

    S. Opitz

Authors
  1. A. D. Gardner
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. S. Opitz
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. C. C. Wolf
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. C. B. Merz
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to A. D. Gardner.

Additional information

This paper is based on a presentation at the AHS 72nd Annual Forum, May 17–19, 2016, West Palm Beach, FL, USA.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Gardner, A.D., Opitz, S., Wolf, C.C. et al. Reduction of dynamic stall using a back-flow flap. CEAS Aeronaut J 8, 271–286 (2017). https://doi.org/10.1007/s13272-017-0237-4

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s13272-017-0237-4

Keywords

Search

Navigation