In this article, the effects of unsteady parameters, concluding mean angle of attack, oscillation amplitude, reduced frequency and pitching axis position, on aerodynamic coefficients of a pitching airfoil are studied. The method, that is employed to analyze the flow field, is described as Coarse Grid CFD (CGCFD) in which the Euler equations are solved using a coarse grid and no slip boundary conditions with compressible surface vorticity confinement technique. Under these conditions, high velocity gradients with great boundary layer growth is appeared which can be controlled by adding a source term of compressible surface vorticity confinement. The required unsteady computational time for this method is drastically lower in comparison with full Navier-Stokes equations solutions even with a simple one equation turbulence model. In this work, it is found that, the computational time for one oscillation loop is reduced more than fifty times. Therefore, finding the numerical results, under many various conditions are available. A multi zone adaptive spring network is applied to simulate the moving boundary, which reduces the computational time. The obtained numerical predictions show a very good accuracy in comparison with experimental data. In this paper, first, results are compared with the experiments in three mean angles of attack with specific oscillation amplitude and reduced frequency. Then, the effect of these parameters and pitching axis positions on aerodynamic coefficients of pitching NACA0015 airfoil is investigated. It is observed that conveyance of pitching axis position to the right or left side and distancing from trailing or leading edges, affects inversely on thickness of the hysteresis loops, maximum, minimum, and average lift and drag coefficients. Enhancing the oscillation amplitude leads to increasing the maximum and average lift and drag coefficients. Further, increasing the reduced frequency results in reduction of the lift hysteresis loop slope and the maximum lift and drag coefficients.

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