Numerical Simulation of Vortex Formation and Convection of Pitching Airfoils Undergoing Dynamic Stall

A Delayed Detached Eddy Simulation approach is employed to investigate vortex formation and convection of dynamic stall during pitching motions of wing sections with NACA 0012 and NACA 0021 airfoil profile sections at transitional Reynolds numbers. The simulations utilize an overset grid framework with six degrees of freedom, enabling non-harmonic pitching profiles. Two-dimensional RANS validations demonstrate excellent agreement with experimental data. The transient three-dimensional DDES results capture key dynamic stall stages: vortex formation, vortex convection, stall onset, and the fully stalled condition. Comparative analysis indicates that DDES is capable of capturing the key features of dynamic stall vortex formation and convection. The use of overset grids for non-harmonic, large-amplitude pitching motions highlights a robust approach for multi-body dynamic simulations.