Measurement of motional model induced 3-D unsteady flow fieldbased on insect hovering

摘要

The combination of the traditional methods of dye visualization and hydrogen bubble visualizationand the 2DPIV makes it more effective to observe and interpret the 3D unsteady flow based on amotional model. The result shows that during the insect flapping the attached leading edge vortex (LEV)should be responsible for the high lift. And the phenomena of the leading edge vortex resembles to thedelta wing leading edge vortex, not only for its configuration but also its breakdown under certainReynolds number. The span-wise flow is the crucial factor to sustain the LEV. Further more, in the startstage of a flapping period, the trailing edge vortex generates and sheds almost simultaneously, whichcan induce a sudden jump of the lift positively.