Department of mechanical engineering, faculty of engineering, Ferdowsi university of Mashhad, Mashhad, Iran
Department of mechanical engineering, faculty of engineering university of Birjand, Birjand, Iran
In this article, the effects of unsteady parameters, including mean angle of attack, oscillation amplitude, and reduced frequency and pitching axis position, on aerodynamic coefficients of a pitching airfoil are studied. This investigation is implemented for high Reynolds number flows around dynamic stall condition. The employed numerical method is a Coarse Grid CFD (CGCFD) method in which the Euler equations are solved using a coarse grid with no slip boundary conditions and compressible surface vorticity confinement technique. The required computational time for this method is significantly lower compared to that of the full Navier-Stokes equations with a simple one equation turbulence model. In addition, a multi zone adaptive spring grid network is applied to simulate the moving boundary which further reduces the computational time. Using the described numerical setup separates the current work from the others’. The obtained numerical predictions are in very good agreement with experimental datafor the high Reynolds number flow. It is found that moving the pitching axis position to the right or left outside and distancing from trailing edge or leading edge, have inverse effects on aerodynamic characteristics. Further, increasing the reduced frequency, results in a reduction of the lift hysteresis loop slope and the maximum lift and drag coefficients.