Validation of a Dynamic Stall Model Extended to Pitching Moment and Drag with Unsteady, Yawed Free-Stream

A state-space, semi-empirical dynamic stall model is presented for use in helicopter flight simulators and onboard flight computers. Dynamic stall is a limiting flight condition for helicopters at high advance ratios and during high-g maneuvers, and to represent it requires the development of reduced-order models that compute loads in real-time. This work validates the stall model of Ref. [1] against wind tunnel tests of NACA 0012 wing sections in unsteady freestream and yawed flow. An improvement of the optimization technique in Ref. [2] is presented to greatly reduce time required to identify parameters.