【作者】 申功炘； 任禹桥； 喻科； 黄烁桥； 谭广琨；

【Author】 G.X.SHEN Y.Q REN Ke YU,S.Q HUANG G.K TAN (Fluid Mechanics Institute,Beijing University of Aeronautics and Astronautics,Beijing,100083,China)

【机构】 北京航空航天大学流体力学研究所；

【摘要】 昆虫(果蝇)悬停飞行中,翅膀按照特定的拍动方式往复运动,产生非定常高升力维持身体的平衡。研究昆虫高升力机理,需要探索拍动翼运动引发的三维空间非定常流场的特性,尤其是三维空间非定常涡的发展变化过程。本文将氢气泡流动显示技术应用于动态模型实验,定性的观察拍动翼前缘涡(LEV)的发展破裂过程。并利用数字体视粒子图像测速,DSPIV(Digital Steroscopic Particle Image Velocimetry)技术,测得了拍动翼运动瞬时相位和相位平均的三维空间流场信息(速度向量场、截面涡量场、空间涡量场,以及三维空间流线),揭示了拍动翼展向流动的存在,并结合定性和定量方法多角度说明了前缘涡沿展向发展到破裂的流动结构,并说明了侧缘涡与前缘涡的相互影响。测量结果表明:在雷诺数960的情况下,拍动翼运动至相位时,翼面上前缘涡在距翼根约60%展长的位置发生破裂;翼根至破裂点之间,展向流动稳定,指向翼梢;破裂点以后,展向流改变方向,指向翼根。更多还原

【Abstract】 When hovering,insect(fruitfly)stabilize its body by flapping its wings reciprocally,in some kind of flapping mode.To investigate the high lift mechanism of insect,it is necessary to analysis the three dimensional un- steady flow field ignited by flapping wing,especially the development and breaking of 3D unsteady vortices. This article,first,achieve the qualitative experiment by using the hydrogen bobble technique on a dynamical model,to depict the life of leading edge vortices from generation to breaking down,and the transmission of it.Also, the DSPIV(Digital Stereoscopic Particle Image Velocimetry)technique was introduced to get the wing’s 3D flow field on a single phase.Expressly,The DSPIV result shows the existence of span-wise flow.Using both qualitative and quantitative methods,this article described the life of the lead edge vortices.The interaction of side edge vortex and leading edge vortex was included in the analysis from this article,as well as the wake of flapping wing. It can be concluded that,at Renolds number 960,when the wing sweep through phaseπ/2,the leading edge vortices break at the 60% along with span length from the root.Between the root and breaking point the span-wise flow keeps stable velocity toward the tip;beyond the breaking point,the span-wise flow reverses its moving direction back to the root.更多还原