Wall-resolved large eddy simulations of a pitching airfoil in deep dynamic stall

This study investigates the flow evolution around a sinusoidal pitching NACA 0012 airfoil, defined by the National Advisory Committee for Aeronautics, undergoing deep dynamic stall using a wall-resolved large eddy simulation (LES) approach. Numerical results are assessed against experimental data from Lee and Gerontakos (2004) at a Reynolds number Re = 135 000 and reduced frequency k = 0.1. A comprehensive analysis of the computational model span size is presented, highlighting the requirement for a span-to-chord ratio of at least one to correctly capture the dynamic stall vortex physics in the downstroke phase. Furthermore, a comparative assessment with state-of-the-art Reynolds-Averaged Navier-Stokes (RANS), hybrid RANS/LES, and the experimental data is carried out. All the numerical models concur to the same flow behavior and exhibit similar differences with the experiments.