Selective frequency damping method for steady RANS solutions of turbulent separated flows around an airfoil at stall

• We extend the Selective Frequency Damping (SFD) Method to the RANS equations.
• The capability of the SFD to reach steady turbulent separated flow solutions is demonstrated.
• We obtain steady flow around an airfoil in pre and post-stall configurations.
• The existence of multiple steady solutions around the stall angle is reported.

The Selective Frequency Damping (SFD) method introduced by Akervik et al. [1] to obtain steady laminar solutions of the Navier-Stokes equations is used to compute steady turbulent solutions of the RANS equations. Coupling the SFD to a classical time step algorithm improves the convergence and robustness of the steady state algorithm. This is demonstrated on the turbulent flow solutions around an airfoil at high Reynolds number (Re ∼ 106) and for angles of attack near stall. The existence of multiple steady solutions, a key element for explaining the hysteresis phenomenon, is reported and described.