Numerical Simulation of a Pitching Naca 0012 Airfoil

This paper describes the application of the noncommercial CFD-code FLOWer to the problem of a sinusoidally pitching NACA 0012 airfoil with high amplitude and reduced frequency under incompressible flow conditions. As FLOWer allows the approximate solution of the nonlinear conservation laws governing viscous fluid flow, i. e. the Navier-Stokes equations, a numerical investigation of the unsteady boundary layer separation occurring during such a motion becomes feasible. Employing FLOWer under the incompressible conditions that correspond to the regarded experimental regime required an extensive preliminary analysis of the numerical parameters imbedded into the code. Having been primarily developed for transonic flow, it was possible to adjust FLOWer to the incompressible flow problem after studying the behavior of its various mechanisms for accelerating convergence and increasing stability. The necessary methodology to obtain optimal parameter settings was developed by critically examining steady state solutions at low angles of attack. The knowledge gained from these cases was then applied to simulate the sinusoidal movement of the NACA 0012 airfoil. FLOWer’s accuracy in predicting the phenomena of the unsteady boundary layer separation was then assessed.