Journal of Aerospace System Engineering (항공우주시스템공학회지)

The Society for Aerospace System Engineering (항공우주시스템공학회)
권호 표지
DOI QR코드

DOI QR Code

Unsteady Aerodynamic Characteristics of an Non-Synchronous Heaving and Pitching Airfoil Part 1 : Frequency Ratio

비동기 히브 및 피치 운동에 따른 에어포일 비정상 공력 특성 Part 1 : 진동 주파수 비

  • Received : 2023.09.24
  • Accepted : 2023.12.06
  • Published : 2023.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

Flapping-wing air vehicles, well known for their free vertical take-off and excellent flight capability, are currently under intensive development and research. While most of the studies have explored the effect of various parameters of synchronized motions on the unsteady aerodynamics of flapping wings, limited attention has been given to the effect of nonsynchronous motions on the unsteady aerodynamic characteristics of flapping wings. In the present study, we conducted a numerical analysis to investigate the unsteady aerodynamic characteristics of an airfoil flapping with different frequency ratios between pitch and heave oscillations. We identified the motions and angle of attacks due to nonsynchronous motions. It was found that the synchronous motion produced thrust with zero lift, but the nonsynchronous motion generated a large lift with little drag. The aerodynamic characteristics of the airfoil undergoing the non-synchronous motion were also analyzed using the vorticity distributions and the pressure coefficient around and on the airfoil. When r was equal to 0.5, larger leading and trailing edge vortices were observed compared to the case when r was equal to 1.0, and these vortices significantly affected the aerodynamic characteristics of the airfoil undergoing the nonsynchronous motion. In future, the effect of pitch amplitude on the unsteady aerodynamic characteristics of the airfoil will be studied.

자유로운 이착륙과 뛰어난 비행능력을 가진 플랩핑 날갯짓 비행체에 관한 집중적 연구개발이 진행되고 있다. 대부분의 플랩핑 날갯짓에 관한 연구는 동기화된 운동의 다양한 운동변수에 대한 연구들로 비동기 운동을 수행하는 에어포일의 비정상 공력 특성에 미치는 영향에 대한 관심은 크지 않았다. 본 연구에서는 히브와 피치 진동운동 주파수가 서로 다른 에어포일의 비정상 공력특성을 수치적으로 연구했다. 먼저 비동기 운동에 따른 운동특성과 받음각 변화를 파악하였다. 해석 결과 진동수 비가 1.0인 경우 양력은 발생하지 않았고 추력이 크게 발생했다. r=0.5인 경우 양력이 크게 발생하였다. 에어포일 주변의와 분포와 표면에서의 압력계수를 분석하여 비동기 진동운동을 하는 에아포일의 공력특성을 분석했다. r=0.5인 경우 r=1.0인 경우 보다 더 큰 앞전 및 뒷전 와들이 관찰되었으며, 이 와들이 비동기 진동운동을 하는 에어포일의 공력특성에 큰 영향을 미친 것을 발견하였다. 향후 피치진동의 진폭이 비동기 진동운동을 하는 에어포일의 비정상 공력특성에 미치는 영향을 연구할 계획이다.

Keywords

Acknowledgement

본 연구는 2022년도 한국교통대학교 지원으로 수행되었음.

References

  1. H. V. Phan, H. C. Park, "Insect-inspired, tailless, hover-capable flapping-wing robots: Recent progress, challenges, and future directions," Progress in Aerospace Sciences, Vol. 111, pp. 1-21, 2019. https://doi.org/10.1016/j.paerosci.2019.100573
  2. J. Han, Y. Han, H. Yang, S. Lee, E. Lee, "A review of flapping mechanisms for avian-inspired flapping-wing air vehicles," Aerospace 2023, Vol. 10, No. 6, pp.1-12, 2023. https://doi.org/10.3390/aerospace10060554
  3. M. F. Platzer, K. D. Jones, "Flapping-wing aerodynamics: progress and challenges," AIAA Journal, Vol. 46, No. 9, 2008.
  4. K. D. Jones, T. C. Lund, M. F. Platzer, "Experimental and computational investigation of flapping wing propulsion of micro air vehicles," Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications, pp. 307-339, 2001.
  5. W. L. Mccrosky, L. W. Carr, K. W. Mcalister, "Dynamic stall experiments on oscillating airfoils." AIAA Journal, Vol. 14, No. 1, 1976.
  6. J. C. S. Lai, M. F. Platzer, "Jet characteristics of a plunging airfoil," AIAA Journal, Vol. 37, No. 12, pp. 1529-1537, 1999. https://doi.org/10.2514/2.641
  7. D. J. Cleaver, Z. Wang, I. Gursul, "Bifurcating flows of plunging airfoils at high Strouhal numbers," Journal of Fluid Mechanics, Vol. 708, pp. 349-376, 2012. https://doi.org/10.1017/jfm.2012.314
  8. M. H. Akbari, S. J. Price, "Simulation of dynamic stall for a NACA 0012 airfoil using a vortex method," Journal of Fluids and Structures, Vol. 17, pp. 855-874, 2003. https://doi.org/10.1016/S0889-9746(03)00018-5
  9. K. Lu, Y. H. Xie, D. Zang, "Numerical study of large amplitude, nonsinusoidal motion and camber effects on pitching airfoil propulsion," Journal of Fluids and Structures, Vol. 36, pp. 184-194, 2013. https://doi.org/10.1016/j.jfluidstructs.2012.10.004
  10. W. Tian, A. Bodling, H. Liu, J. C. Wu, G. He, H. Hu, "An experimental study of the effects of pitch-pivot location on the propulsion performance of a pitching airfoil," Journal of Fluids and Structures, Vol. 60, pp. 130-142, 2016. https://doi.org/10.1016/j.jfluidstructs.2015.10.014
  11. J. Sinha, J. B. Lua, S. M. Dash, "Influence of the pivot location on the thrust and propulsive efficiency performance of a two-dimensional flapping elliptic airfoil in a forward flight," Physics of Fluids, Vol. 38, No. 8, 2021.
  12. R. Sankarasubramanian, A. Sridhar, M. S. Prashanth, A. Mohammad, R. K. Velamati, L. Vaitla, "Influence of thickness on performance characteristics of non-sinusoidal plunging motion of symmetric airfoil," Aerospace Science and Technology, Vol. 81, pp. 333-347, 2018. https://doi.org/10.1016/j.ast.2018.08.007
  13. M. Thankor, G. Kumur, D. Das, A. De, "Investigation of asymmetrically pitching airfoil at high reduced frequency," Physics of Fluids, Vol. 32, pp. 1-17, 2020 https://doi.org/10.1063/5.0006659
  14. S. Yang, C. Liu, J. Wu, "Effect of motion trajectory the aerodynamic performance of a flapping airfoil," Journal of Fluids and Structures, Vol. 75, pp. 213-232, 2017. https://doi.org/10.1016/j.jfluidstructs.2017.08.009
  15. P. Tisovska, "Description of the overset mesh approach in ESI version of OpenFOAM," In Proceedings of CFD with OpenSource Software, 2019.
  16. T. Wu, B. Song, W. Song, W. Yang, D. Xue, Z. Han, "Lift performance enhancement for flapping airfoils by considering surging motion," Chinese Journal of Aeronautics, Vol. 35, No.9, pp. 194-207, 2022. https://doi.org/10.1016/j.cja.2021.11.015
  17. Z. Wang, X. Chang, L. Hou, N. Gao, W. Chen, Y. Tian, "Optimal matching of flapping hydrofoil propulsion performance considering interaction effects of motion parameters," Journal of Marine Science and Engineering, Vol. 10, No. 7, pp. 1-20, 2022. https://doi.org/10.3390/jmse10070853
  18. D. D. J. Chandar, M. Damodaran, "Computational study of unsteady low-Reynolds number airfoil aerodynamics using moving overlapping meshes," AIAA Journal, Vol. 46, No. 2, 2008.
  19. S. Volkner, J. Brunswing, T. Rung, "Analysis of non-conservative interpolation techniques in overset grid finite-volume methods," Computers and Fluids, Vol. 148, No. 22, pp. 39-55, 2017. https://doi.org/10.1016/j.compfluid.2017.02.010
  20. A. K. M and S. G, N. Naik, "Implementation of Higher-order PIMPLE Algorithm for Time Marching Analysis of Transonic Wing Compressibility Effects with High Mach Pre-conditioning," Engineered Science, Vol. 20, 2022.