Micro air vehicles(MAV) with a maximal dimension of 15cm or less and a flight speed of 10m/s have been of interests to both military and civilian application. Lately, there has been growing interest in developing the flexible wings MAVs, which has been discovered that there are many advantages compared to the rigid wing. The investigation of the flexible wing is essentially in the field of fluid-structure coupling, the basic characteristic of which is the interaction of the two media. In this paper, a loosely coupled algorithm is presented in order to solve the fluid-structure coupling, we denote by loose coupling the separate update of the CFD (Computational Fluid Dynamics) and CSD (Computational Structure Dynamics) domains, with a transfer of variables at the interface, not the simultaneous update of all variables. Then, by numerically simulating the fluid field of the rigid and flexible wings which have the same shape at different angles of attack, and comparing the aerodynamics of them, one advantage of a flexible wing can be founded: it can facilitate passive shape adaptation, which has two effects: one is lowering the effective angles of attack, the other is increasing the camber. It is typically for the lager angles of attack. It also can be founded that the flexible wing can increase the stall angle of attack of the Micro air vehicle. |