**2.1.1 Introduction**

Numerical method for solution of unsteady flow over airfoil oscillating in incompressible, inviscid flow field is based on well known panel method in form developed for steady flow by Hess and Smith. Due to unsteadiness in addition to boundary conditions, additional conditions are necessary. Kelvin theorem and Kutta condition is to be applied in unsteady form. This results with a nonlinear problem.
