Critical indicators of dynamic stall on a finite wing

Dynamic stall is a classic unsteady aerodynamic phenomenon. Extensive two-dimensional research has been conducted over the past decades, and the prediction of critical flow events, such as leading-edge vortex initiation, has attracted considerable attention. However, there remains a lack of adequate theoretical frameworks and effective approaches for the real-time prediction of three-dimensional (3D) critical flow events. In this study, numerical simulations were conducted on the 3D unsteady flow field of a finite-aspect-ratio wing under periodic pitching oscillations. Two critical indicators for dynamic stall, namely, the spatial distribution coefficient of pressure (SDCP) and the leading-edge suction parameter, were evaluated using the raw 3D simulation data. A new definition of the spanwise SDCP is proposed to predict various complex 3D flow events over a finite wing. Validation cases with different numbers of pressure transducers verified the feasibility of SDCP. The present results enable real-time and multi-dimensional monitoring of flow states over the finite-aspect-ratio wing.