Abstract

Two-dimensional aerodynamic models of unsteady flapping wing motions are analyzed with focus on advanced rotation and the wing's rotation axis to explain the force peak at the end of each half stroke. In this model, the translational velocity of the wing along the stroke plane is constant for most of the time except near end and the beginning of each stroke where it slows down to zero and then speeds up again for the next stroke. The flapping wing motions with various combination of controlled translational and rotational velocity of the wings along horizontal or inclined stroke planes with straight-line trajectory are investigated numerically through two-dimensional Navier-Stokes solutions. CFD programs based on Finite Volume Method are used to simulate the flow around a thin airfoil in combined translational and rotational motions. The simulation provides the flow patterns, pressure fields from which the aerodynamic forces and moments are obtained.