Effects of uniform vertical inflow perturbations on the performance of flapping wings

Royal Society Open Science

Noriyasu Ando¹  Fang-Bao Tian²  John Young²  Sridhar Ravi²  Soudeh Mazharmanesh²  Jace Stallard²  Alex Fisher³  Albert Medina⁴ 

[1] Department of System Life Engineering, Maebashi Institute of Technology, Maebashi 371-0816, Japan;School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600, Australia;School of Engineering, RMIT University, Melbourne, 3083, Australia;US Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433, USA;

关键词: flapping wings;    wind gusts;    vertical inflows;    disturbances;    wake interaction;   

DOI  :  10.1098/rsos.210471

来源: DOAJ

【 摘 要 】

Flapping wings have attracted significant interest for use in miniature unmanned flying vehicles. Although numerous studies have investigated the performance of flapping wings under quiescent conditions, effects of freestream disturbances on their performance remain under-explored. In this study, we experimentally investigated the effects of uniform vertical inflows on flapping wings using a Reynolds-scaled apparatus operating in water at Reynolds number ≈ 3600. The overall lift and drag produced by a flapping wing were measured by varying the magnitude of inflow perturbation from JVert = −1 (downward inflow) to JVert = 1 (upward inflow), where JVert is the ratio of the inflow velocity to the wing's velocity. The interaction between flapping wing and downward-oriented inflows resulted in a steady linear reduction in mean lift and drag coefficients, [Formula: see text] and [Formula: see text], with increasing inflow magnitude. While a steady linear increase in [Formula: see text] and [Formula: see text] was noted for upward-oriented inflows between 0 < JVert < 0.3 and JVert > 0.7, a significant unsteady wing–wake interaction occurred when 0.3 ≤ JVert < 0.7, which caused large variations in instantaneous forces over the wing and led to a reduction in mean performance. These findings highlight asymmetrical effects of vertically oriented perturbations on the performance of flapping wings and pave the way for development of suitable control strategies.

【 授权许可】

Unknown