On the Prediction of Dynamic Stall Onset on Airfoils in Low Speed Flow

Abstract

A computational approach is described for the rapid and systematic prediction and evaluation of the onset of dynamic stall due to rapid incidence changes or unsteady pitch or plunge motions. The method combines an unsteady, two-dimensional panel code with a two-dimensional boundary-layer code. The panel code provides incompressible, inviscid flowfields about arbitrary airfoils undergoing prescribed motions. The boundary-layer code computes laminar, transitional and turbulent regimes. Presented results demonstrate that the delay in dynamic stall onset is directly related to the dynamic pressure lag, in agreement with previous Navier-Stokes simulations. Also, results are presented showing the effect of airfoil shape and Reynolds number on the onset of dynamic stall.