Analysis of light dynamic stall using dynamic mode decomposition – IFASD 2019-036

This study presents an analysis of dynamic stall using dynamic modal decomposition (DMD). The hybrid, delayed detached eddy simulations, with a k - ? SST turbulence model, were employed to perform the dynamic stall simulations for a pitching NACA 0012 airfoil, at a Mach number of 0.3 and a Reynolds number of 4 × 10⁶. With a mean angle of attack of 11^? and peak pitching amplitude of 5^?, the dynamic stall observed here can be considered to be in the light stall regime, where potential energy transfer from the flow to the airfoil’s motion is often observed. DMD analysis of the pressure snapshots was performed to investigate the modal behavior representing the various physical phenomena of light stall at high, turbulent Reynolds number. The stochastic nature of the turbulent dynamic stall phenomenon was also investigated by comparing the DMD pressure modes from various cycles of the pitching airfoil motion to the phase-averaged DMD pressure modes.