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Measurements of the Laminar-Separated Region on the Airfoil with Actively Deflected Flap

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Abstract

Recently, the study of flow around an airfoil at the low Reynolds numbers region has become increasingly important. At low Reynolds numbers, a laminar boundary layer separates from the airfoil and the laminar-separated region is formed. Previous studies demonstrated that deflecting the trailing-edge flap affects the flow downstream of the laminar-separated region. This study investigates flow pattern changes in the laminar-separated region when the flap deflection angle is dynamically altered. In this study, the NACA0012 airfoil (Re = \({2.0\times 10}^{4}\)) was used. The flap was attached at the trailing-edge, and the trailing-edge flap angle (\(\delta \)) was changed from \(5^\circ \) to \(20^\circ \) at 0.5, 1, and 3 Hz (round trip) and from 10° to 30° at 0.5, 1, and 3 Hz (round trip). The velocity distributions around the airfoil were measured using time-resolved two-dimensional particle image velocimetry (PIV). It has been discovered that the larger the angle of attack and the flap angle, the larger the size of the vortex and the smaller the number of vortices emitted. The frequencies of the vortex emission when the flap is vibrated smoothly connect the results between the two cases where the flap angle is fixed. This suggests that when the flap is vibrated, the characteristics of the separated flow are highly dependent on the flap angle.

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References

  1. Elbanhawi M, Mohamed A, Clothier R, Palmer JL, Simic M, Watkins S (2017) Enabling technologies for autonomous MAV operations. Prog Aerosp Sci. https://doi.org/10.1016/j.paerosci.2017.03.002

    Article  Google Scholar 

  2. Tatumi T, Gotou K (1976) Flow stability theory, industrial books (in Japanese)

  3. Michelis T, Yarusevych S, Kotsonis M (2018) On the origin of spanwise vortex deformations in laminar separation bubbles. J Fluid Mech 841:81–108. https://doi.org/10.1017/jfm.2018.91

    Article  MATH  Google Scholar 

  4. Hama FR, Long JD, Hegarty JC (1957) On transition from laminar to turbulent flow. J Appl Phys 28:388–394. https://doi.org/10.1063/1.1722760

    Article  Google Scholar 

  5. Hama FR (1963) Progressive deformation of a perturbed line vortex filament. Phys Fluids 6:526–534. https://doi.org/10.1063/1.1706768

    Article  MATH  Google Scholar 

  6. Tani I (1964) Low-speed flows involving bubble separations. Prog Aeronaut Sci. https://doi.org/10.1016/0376-0421(64)90004-1

    Article  Google Scholar 

  7. Mueller TJ, Batill SM (1982) Experimental studies of separation on a two-dimensional airfoil at low Reynolds numbers. AIAA J. https://doi.org/10.2514/3.51095

    Article  Google Scholar 

  8. Laitone EV (1977) Wind tunnel tests of wings at Reynolds numbers below 70000. Exp Fluids. https://doi.org/10.1007/s003480050128

    Article  Google Scholar 

  9. Chandra S (2020) Low Reynolds number flow over low aspect ratio corrugated wing. Int J Aeronaut Space Sci 21:627–637. https://doi.org/10.1007/s42405-019-00247-5

    Article  Google Scholar 

  10. Lambert A, Yarusevych S (2019) Effect of angle of attack on vortex dynamics in laminar separation bubbles. Phys Fluids. https://doi.org/10.1063/1.5100158

    Article  Google Scholar 

  11. Eljack E, Soria J, Elawad Y, Ohtake T (2021) Simulation and characterization of the laminar separation bubble over a NACA-0012 airfoil as a function of angle of attack. Phys Rev Fluids 6:034701. https://doi.org/10.1103/PhysRevFluids.6.034701

    Article  Google Scholar 

  12. Hattori J, Sunada Y, Rinoie K (2018) Time-series flow velocity distribution measurement for separation flow occurring on NACA0012 airfoil in low Reynolds number region. In: Proc. JSASS 49th annual meeting, JSASS-2018-1011 (in Japanese)

  13. Sakita H, Rinoie K (2020) Consideration on vortex structure development in the airfoil upper flow dissection area by time series PIV measurement. In: Proc. JSASS fluid dynamic conference, JSASS-2020-2026-F+A (in Japanese)

  14. Liao JC, Beal DN, Lauder GV, Triantafyllou MS (2003) Fish exploiting vortices decrease muscle activity. Science 302:1566–1569

    Article  Google Scholar 

  15. Kang W, Lei P, Zhang J, Xu M (2015) Effects of local oscillation of airfoil surface on lift enhancement at low Reynolds number. J Fluids Struct. https://doi.org/10.1016/j.jfluidstructs.2015.05.009

    Article  Google Scholar 

  16. Rennie RM, Jumper EJ (1996) Experimental measurement of dynamic control surface effectiveness. J Aircr. https://doi.org/10.2514/3.47030

    Article  Google Scholar 

  17. The Visualization Society of Japan (2002) Handbook of particle image velocimetry. Morikita Press, Tokyo, pp 137–164 (in Japanese)

    Google Scholar 

  18. Nakae Y, Ohtake T, Muramatsu A, Motohashi T (2011) Three dimensionalization of the flow field around a NACA0012 airfoil at low Reynolds numbers. J Jpn Soc Aeronaut Space Sci (in Japanese). https://doi.org/10.2322/jjsass.59.244

    Article  Google Scholar 

  19. Nguyen HA, Mizoguchi M, Itoh H (2020) Unsteady flow field around NACA0012 airfoil undergoing constant pitch rates at low Reynolds numbers. In: AIAA Aviation 2020 Forum. https://doi.org/10.2514/6.2020-3041

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Funding

This work was supported by Japan Society for the Promotion of Science KAKENHI Grant number JP17H93476.

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Authors and Affiliations

  1. Graduate Student, Department of Aeronautics and Astronautics, The University of Tokyo, Tokyo, Japan

    Yuta Akama

  2. Professor, Department of Aeronautics and Astronautics, The University of Tokyo, Tokyo, Japan

    Kenichi Rinoie

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  1. Yuta Akama
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  2. Kenichi Rinoie
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Correspondence to Yuta Akama.

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An earlier version of this paper was presented at APISAT 2021, Jeju, South Korea, in November 2021.

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Akama, Y., Rinoie, K. Measurements of the Laminar-Separated Region on the Airfoil with Actively Deflected Flap. Int. J. Aeronaut. Space Sci. 23, 660–669 (2022). https://doi.org/10.1007/s42405-022-00472-5

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  • DOI: https://doi.org/10.1007/s42405-022-00472-5

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