An Investigation of the Numerical Prediction of Static and Dynamic Stall

The accurate prediction of airloads on rotorcraft is dependent on the capability of the flow solver to correctly capture the viscous flow field characteristics at all angles of attack including in both static and dynamic conditions. Analysis of different airfoils indicates that transition aids in the prediction of static and dynamic stall, but that the turbulence models are still over predicting the stall location. Modifications to the Spalart-Allmaras constants, which were originally computed for attached and mildly separated flows, are explored with success for both static and dynamic stall. Finally, comparisons with Large Eddy Simulations (LES) show that LES has the capability to predict the aerodynamic coefficients fairly accurately with much coarser grids, leading to potential use of these methods in parallel computing.