Water tunnel experimental investigation on the aerodynamic performance of flapping wings for nano air vehicles

摘要

The aerodynamics of flapping wings is ultimately concerned with the relation between motion kinematics and the time-history of aerodynamic forces and moments. But an important intermediate quantity is the evolution of the flow field - and in particular of flow separation. Nature's solution to large time-varying pressure gradients, for example those due to aggressive motions, is to form and eventually to shed vortices. We are interested in understanding and exploiting these vortices - for example, in delaying vortex shedding to promote lift in situations where flow separation is in any case inevitable. From the engineering viewpoint, the question is to what extent closed-form models and conventional numerical/analytical tools can estimate the aerodynamic force history, with an eye to eventually running large parameter studies and optimizations. Our paper contain results of water tunnel experiments on flapping wings aeromechanics. The idea of investigation is to optimize the wing trajectories, and to find methods providing stability and control. In the article we present, also, conception and methodology of tests. The investigation is divide into two parts: preliminary and principal tests. The aim of initial part is to extract quasi - state characteristic for wings of different platforms shapes. This characteristic will be used to generate initial kinematics of movement of wing. It will be initial point of further tests. The purpose of the main experiment is to find the best way of movement for wing taking account all of unsteady phenomena (interaction between vortices, wing - wing interference, etc). Finally we want to identify efficient way of controlling nano-microelectromechanical flying insect (entomopter).