The purpose of this paper is to investigate the effect of unsteady trailing edge flapping on lift generation for fixed airfoils at low angles of attack. To do this, a 2D unsteady compressible flow around a fixed airfoil is analyzed at different angles of incidence by means of Coarse Grid CFD (CGCFD) method with spring dynamic network. In this method Euler system of equation is solved with coarse Grid and no slip boundary condition using vorticity confinement technique. At first for code validation, the results of fixed airfoil at different angles of attack and also pitching airfoil are compared with experiments. Further, the CGCFD consequences are compared with the results of RANS with SA turbulent model in the quasi steady case. Then trailing edge flapping (TEF) is added to the fixed airfoil at low angles of attack. The effects of unsteady parameters such as the amplitude and the frequency of TEF are investigated at different low angles of attack. The results show that in a specific low angle of attack, adding TEF results in increasing the lift coefficient comparing with the fixed airfoil without TEF.