Skip to main content
SpringerLink
Log in

A New Study on the Gap Effect of an Airfoil with Active Flap Control Based on the Overset Grid Method

  • Original Paper
  • Published:
International Journal of Aeronautical and Space Sciences Aims and scope Submit manuscript

Abstract

Rotors with active flap control have considerable potential in reducing vibration and noise and improving aerodynamic performance. However, due to the movement of the flap, there are unavoidable gaps between the components that will lead to significant changes in the aerodynamic characteristics. Moreover, considering the difficulties in motion modeling and the accuracy of the simulation of the flow field in such a narrow gap, carrying out related research is challenging; thus, there has been inadequate targeted research, and that which does exist requires supplementation. To carry out this challenging flow field simulation, the overset assembly algorithm proposed by the author in previous research is adopted in the present study. It is used to successfully assemble the narrow gap, and the accuracy of the simulation is fully verified by comparing the results with the actual experimental results and a grid study. Furthermore, to compensate for the lack of research and experiments on the gap effect, cases considering a complete range of gap widths from an absence of a gap to a width of 10% of the chord length are set up and carried out under the following three case groups: steady cases with a fixed trailing-edge deflection angle, unsteady cases in which only the trailing-edge flap is flapping, and full-motion cases characterized by the periodic flap of the main airfoil and the trailing-edge flap. The results show that the gap increases the drag of the trailing-edge flap and decreases aerodynamic efficiency, especially at low speeds and high angles of attack. Nevertheless, when the gap is unavoidable, there is a range of the gap width that makes unapparent the decrease of aerodynamic efficiency. Moreover, the decrease of aerodynamic efficiency can be reduced as much as possible by a well-designed gap region geometry to ensure that the airfoil and the trailing-edge flap fit together when moving.

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
Fig. 27
Fig. 28
Fig. 29

Similar content being viewed by others

References

  1. Friedmann PP, Millott TA (1995) Vibration reduction in rotorcraft using active control—a comparison of various approaches. J Guidance, Control, Dynamics 18(4):664–673. https://doi.org/10.2514/3.21445

    Article  Google Scholar 

  2. Roth D, Enenkl B, Dieterich O (2006) Active rotor control by flaps for vibration reduction—full scale demonstrator and first flight test results. Paper presented at the 32nd European Rotorcraft Forum, Maastricht, The Netherlands, 2006

  3. Straub FK, Kennedy DK, Domzalski DB, Hassan AA, Ngo H, Anand V, Birchette T (2016) Smart material-actuated rotor technology—SMART. J Intell Mater Syst Struct 15(4):249–260. https://doi.org/10.1177/1045389x04042795

    Article  Google Scholar 

  4. Straub FK, Anand VR, Birchette TS, Lau BH (2009) SMART rotor development and wind tunnel test. Paper presented at the 35th European Rotorcraft Forum, Hamburg, 2009

  5. Gerontakos P, Lee T (2008) PIV study of flow around unsteady airfoil with dynamic trailing-edge flap deflection. Exp Fluids 45(6):955–972. https://doi.org/10.1007/s00348-008-0514-4

    Article  Google Scholar 

  6. Birch D, Lee T (2005) Effect of trailing-edge flap on a tip vortex. J Aircraft 42(2):442–447. https://doi.org/10.2514/1.6749

    Article  Google Scholar 

  7. Hassan AA, Straub FK, Noonan KW (2000) Experimental/numerical evaluation of integral trailing edge flaps for helicopter rotor applications. Paper presented at the the 56th Annual Forum of the American Helicopter Society, Virginia Beach, 2000

  8. Kamliya Jawahar H, Ai Q, Azarpeyvand M (2017) Experimental and numerical investigation of aerodynamic performance of airfoils fitted with morphing trailing-edges. Paper presented at the 23rd AIAA/CEAS Aeroacoustics Conference

  9. Feszty D, Gillies EA, Vezza M (2004) Alleviation of airfoil dynamic stall moments via trailing-edge flap flow control. AIAA J 42(1):17–25. https://doi.org/10.2514/1.853

    Article  Google Scholar 

  10. Milgram JH (1997) A comprehensive aeroelastic analysis of helicopter main rotors with trailing edge flaps for vibration reduction. University of Maryland

  11. Aoyama T, Yang C, Kondo N, Saito S (2006) Comparison of noise reduction effect between AFC and conventional IBC by moving overlapped grid method. Paper presented at the 12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference)

  12. Aoyama T, Yang C, Saito S (2005) Numerical analysis of active flap for noise reduction using moving overlapped grid method. Paper presented at the the American Helicopter Society 61st Forum, Grapevine, 2005

  13. Nakao M, Saito S (2004) Research for The BVI noise reduction using the blade active control. Paper presented at the 30th European Rotorcraft Forum, Marseille, 2004

  14. Shen J, Chopra I (2004) Swashplateless helicopter rotor with trailing-edge flaps. J Aircraft 41(2):208–214. https://doi.org/10.2514/1.9279

    Article  Google Scholar 

  15. Liggett N, Smith MJ (2013) The physics of modeling unsteady flaps with gaps. J Fluids Struct 38:255–272. https://doi.org/10.1016/j.jfluidstructs.2012.12.010

    Article  Google Scholar 

  16. Krzysiak A, Narkiewicz J (2006) Aerodynamic loads on airfoil with trailing-edge flap pitching with different frequencies. J Aircraft 43(2):407–418. https://doi.org/10.2514/1.15597

    Article  Google Scholar 

  17. Gagliardi, Adriano, Barakos GN (2006) Improving hover performance of low-twist rotors using trailing-edge flaps—a computational study. Paper presented at the 32nd European Rotorcraft Forum, Maastricht, 2006

  18. Liu L, Padthe AK, Friedmann PP, Quon E, Smith MJ (2009) Unsteady aerodynamics of flapped airfoils and rotors using CFD and approximate methods. Paper presented at the the American Helicopter Society 65th Annual Forum, Grapevine, 2009

  19. Liu L, Padthe AK, Friedmann PP, Quon E, Smith MJ (2011) Unsteady aerodynamics of an airfoil/flap combination on a helicopter rotor using computational fluid dynamics and approximate methods. J Am Helicopter Soc 56(3):1–13. https://doi.org/10.4050/jahs.56.032003

    Article  Google Scholar 

  20. Jose A, Baeder J (2009) Steady and unsteady aerodynamic modeling of trailing edge flaps with overhang and gap using CFD and lower order models. Paper presented at the 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition

  21. Jain R, Yeo H, Chopra I (2012) Investigation of trailing-edge flap gap effects on rotor performance using CFD-CSD coupling. Paper presented at the 50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition

  22. Jain R, Yeo H, Chopra I (2013) Investigation of trailing-edge flap gap effects on rotor performance using high-fidelity analysis. J Aircraft 50(1):140–151. https://doi.org/10.2514/1.C031837

    Article  Google Scholar 

  23. Potsdam M, Fulton MV, Dimanlig A (2010) Multidisciplinary CFD/CSD analysis of the smart active flap rotor. Paper presented at the the American Helicopter Society 66th Annual Forum, Phoenix, 2010

  24. Zhu WJ, Behrens T, Shen WZ, Sørensen JN (2013) Hybrid immersed boundary method for airfoils with a trailing-edge flap. AIAA J 51(1):30–41. https://doi.org/10.2514/1.J051446

    Article  Google Scholar 

  25. Hu Z, Xu G, Shi Y (2020) A robust overset assembly method for multiple overlapping bodies. Int J Numer Meth Fluids. https://doi.org/10.1002/fld.4903

    Article  Google Scholar 

  26. Pascioni KA, Cattafesta LN (2014) An experimental investigation of the 30P30N multi-element high-lift airfoil. Paper presented at the 20th AIAA/CEAS Aeroacoustics Conference (35th AIAA Aeroacoustics Conference), Atlanta, Georgia, 2014

  27. Spaid FW (2000) High reynolds number, multielement airfoil flowfield measurements. J Aircraft 37(3):499–507. https://doi.org/10.2514/2.2626

    Article  Google Scholar 

  28. Landon RH (1982) NACA 0012 oscillatory and transient pitching. AGARD R-702

Download references

Acknowledgements

A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

Author information

Authors and Affiliations

  1. Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China

    Zhiyuan Hu, Guohua Xu & Yongjie Shi

Authors
  1. Zhiyuan Hu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Guohua Xu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Yongjie Shi
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Guohua Xu.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Hu, Z., Xu, G. & Shi, Y. A New Study on the Gap Effect of an Airfoil with Active Flap Control Based on the Overset Grid Method. Int. J. Aeronaut. Space Sci. 22, 779–801 (2021). https://doi.org/10.1007/s42405-021-00364-0

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s42405-021-00364-0

Keywords

Search

Navigation