Numerical Investigation of Three-dimensional Dynamic Stall on an Oscillating Finite Wing

Three-dimensional numerical computations using ONERA's structured elsA code and the unstructured DLR-TAU code are compared with the OA209 finite wing experiments in static stall and dynamic stall conditions at a Mach number of 0.16 and a Reynolds number of 1 x 10⁶. The DLR-TAU computations were run with the Spalart-Allmaras and Menter SST turbulence models, and the elsA computations were carried out using the Spalart-Allmaras and the k-ω Kok + SST turbulence models. Although comparable grids were used the static simulations show large discrepancies in the stall region between the structured and unstructured approaches. Large differences for the three-dimensional dynamic stall case are obtained with the computations using the Spalart-Allmaras turbulence model showing no flow separation in contrast to the experiment. The three-dimensional dynamic stall computations with the two-equation turbulence models are in good agreement with the unsteady pressure measurements and flow field visualizations of the experiment, but also show a shift in the stall angle compared to the experiment. The analysis of the flow field around the finite wing using the numerical simulations reveals the evolution of the Ω-shaped vortex, generated by the interaction of the blade tip vortex.