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摘要:
昆虫在自然界中飞行时多会受到侧风的干扰,因此了解侧风作用下昆虫拍动翅上气动力的变化对昆虫飞行机理的研究工作具有重要意义。应用计算流体力学(CFD)方法模拟了存在侧风时拍动翅上绕流,并与正常悬停情况进行对比,从侧风的方向和强度2个方面考察了其对拍动翅气动特性的影响。结果表明:侧风对拍动翅气动特性的改变包含2个流动机制的贡献,即相对速度效应和前缘涡轴向速度效应,且从翅尖吹向翅根的侧风与从翅根吹向翅尖的侧风对气动力的影响有着显著的不同;而不同强度的同向侧风下,气动力的改变类似,仅存在数值上的差异。
Abstract:Insects are often disturbed by lateral wind when flying in nature. Thus understanding the variation of aerodynamic force of the flapping wing under the lateral wind is significant to the research on flying mechanism of insects. The fluid fields around the flapping wing under the lateral winds were simulated using the method of computational fluid dynamic (CFD), which were then compared with the hovering situation (with no lateral wind), and the effects of the dynamic characteristics of flapping wing was investigated from two aspects of the strength and direction of the lateral wind. The results indicate that the lateral wind has two contributions to the aerodynamics of the flapping wing:one is "changing-relative-velocity" effect, and the other is "changing-LEV-axial-velocity" effect. Lateral winds in different directions (from wing-tip to wing-root or from wing-root to wing-tip) have obviously different effect on the aerodynamics; however, under lateral winds with different intensities but the same direction, the variations of aerodynamic force are similar, and there are only numerical differences.
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Key words:
- lateral wind /
- insect /
- aerodynamic force /
- hovering /
- numerical simulation
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[1] ELLINGTON C P, VAN DEN BERG C, WILLMOTT A P, et al.Leading-edge vortices in insect flight[J].Nature, 1996, 384:626-630. doi: 10.1038/384626a0 [2] BIRCH J M, DICKINSON M H.Spanwise flow and the attachment of the leading-edge vortex on insect wings[J].Nature, 2001, 412(6848):729-733. doi: 10.1038/35089071 [3] SUN M, TANG J.Unsteady aerodynamic force generation by a model fruit fly wing in flapping motion[J].Journal of Experimental Biology, 2002, 205(1):55-70. http://www.ncbi.nlm.nih.gov/pubmed/11818412 [4] MOU X L, LIU Y P, SUN M.Wing motion measurement and aerodynamics of hovering true hoverflies[J].Journal of Experimental Biology, 2011, 214(17):2832-2844. doi: 10.1242/jeb.054874 [5] DUDLEY R, ELLINGTON C.Mechanics of forward flight in bumblebees:Ⅱ.Quasi-steady lift and power requirements[J].Journal of Experimental Biology, 1990, 148(1):53-88. http://jinsectscience.oxfordjournals.org/lookup/ijlink?linkType=ABST&journalCode=jexbio&resid=148/1/53&atom=%2Fjis%2F14%2F1%2F159.atom [6] MENG X G, SUN M.Wing kinematics, aerodynamic forces and vortex-wake structures in fruit-flies in forward flight[J].Journal of Bionic Engineering, 2016, 13(3):478-490. doi: 10.1016/S1672-6529(16)60321-9 [7] SHEN C, SUN M.Dynamic flight stability of a model dronefly in vertical flight[J].Acta Mechanica Sinica, 2014, 30(6):828-838. doi: 10.1007/s10409-014-0110-1 [8] SHEN C, SUN M.Power requirements of vertical flight in the dronefly[J].Journal of Bionic Engineering, 2015, 12(2):227-237. doi: 10.1016/S1672-6529(14)60115-3 [9] LIU Y, SUN M.Wing kinematics measurement and aerodynamics of hovering droneflies[J].Journal of Experimental Biology, 2008, 211(13):2014-2025. doi: 10.1242/jeb.016931 [10] ELLINGTON C.The aerodynamics of hovering insect flight.Ⅲ.Kinematics[J].Philosophical Transactions of the Royal Society of London.Series B, Biological Sciences, 1984, 305(1122):41-78. doi: 10.1098/rstb.1984.0051 [11] ROGERS S E, KWAK D, KIRIS C.Numerical solution of the incompressible Navier-Stokes equations for steady-state and time-dependent problems[J].AIAA Journal, 1991, 29(4):603-610. doi: 10.2514/3.10627 [12] SUN M, XIONG Y.Dynamic flight stability of a hovering bumblebee[J].Journal of Experimental Biology, 2005, 208(Pt 3):447-459. https://www.ncbi.nlm.nih.gov/pubmed/15671333 [13] ZHANG Y, SUN M.Dynamic flight stability of a hovering model insect:Lateral motion[J].Acta Mechanica Sinica, 2010, 26(2):175-190. doi: 10.1007/s10409-009-0303-1 [14] SUN M, WU J H.Aerodynamic force generation and power requirements in forward flight in a fruit fly with modeled wing motion[J].Journal of Experimental Biology, 2003, 206(17):3065-3083. doi: 10.1242/jeb.00517 [15] WU J H, SUN M.Unsteady aerodynamic forces of a flapping wing[J].Journal of Experimental Biology, 2004, 207(7):1137-1150. doi: 10.1242/jeb.00868 [16] SUN M, YU X.Aerodynamic force generation in hovering flight in a tiny insect[J].AIAA Journal, 2006, 44(7):1532-1540. doi: 10.2514/1.17356 [17] WU J, SUN M.Control for going from hovering to small speed flight of a model insect[J].Acta Mechanica Sinica, 2009, 25(3):295-302. doi: 10.1007/s10409-009-0241-y [18] XU N, SUN M.Lateral dynamic flight stability of a model bumblebee in hovering and forward flight[J].Journal of Theoretical Biology, 2013, 319:102-115. doi: 10.1016/j.jtbi.2012.11.033 [19] DICKINSON M H, LEHMANN F O, SANE S P.Wing rotation and the aerodynamic basis of insect flight[J].Science, 1999, 284(5422):1954-1960. doi: 10.1126/science.284.5422.1954