In this numerical study, the flow field around an airfoil undergoing a flapping motion or oscillation is considered and the effect of the amplitude of oscillation, the frequency and the angle of attack are investigated. To adapt grids, when bodies move or rotate, the spring network analysis is used. In this paper grid edges are replaced with linear springs which are balanced in several iterates. A logical definition is assumed for linear spring coefficient and displacement of nodes. All we have done are for structured meshes for airfoils. Then boundaries are moved or rotated and meshes are refined by using spring network analogy. The two dimensional, incompressible and viscous governing equations are solved using a finite-volume discretization technique. The results are compared well for drag and lift coefficient with other numerical results. By comparing, it is obvious that the aerodynamic forces and moments are not only a function of the incidence angle but also is dependent to oscillatory quantities.

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