Abstract:
Complexities in hummingbird scale flapping wing aerodynamics pose significant challenges to the design of flapping wing micro air vehicles (MAVs). These challenges arise from the unsteady nature of the aerodynamic loads and flow field, which consists of highly viscous flow coupled with complicated wing kinematics. The current study introduces a CFD simulation to understand the force generation and flow structure of flexible flapping wing. The CFD analysis used a compressible Reynolds-averaged Navier-Stokes solver to resolve the complex, highly vortical, three-dimensional flow. The objectives of the effort were to understand the unsteady aerodynamic mechanisms and their relation to force production on a rigid wing undergoing an avian-type flapping motion. The results comparison between simulation and experiment suggest a number of potential causes for discrepancies in force predictions, including the effect of complex deformation and the development of a vortex pair that becomes attached to the wing at stroke reversal which appears to be dependant on minor details of the wing geometry.