Because of the development of computer power and algorithm of numerical method, unsteady and turbulent flow with large separation region can be solved. The flows around oscillating airfoil is analyzed by solving the Euler eqation in the case of no stall problem and the Navier-Stokes' equation with k-ε turbulence model in the case of both no stall and stall problems. Finite volume method is applied using unstructured gird, upwind scheme and explicit time integration and in inviscid flow analysis, implicit time integration is used also. In the case of light stall problem, stall phenomenon is captured but too much computation time is required and in the case of deep stall problem the solution cannot be obtained. If the advantages of unstructured grid such as grid adaptation are used, calculation of deep stall will be possible and the solution obtained will be better. Inviscid flow analysis shows that implicit time integration will reduce computation time.
