Prediction of post-stall aerodynamic characteristics of wing(S) with separated flow modeled as a single nascent vortex

A numerical iterative vortex lattice method is developed for post-stall flow past wing(s) where the separated flow is modeled using NY nascent vortex flaments. The wing itself is modeled using NX x NY bound vortex rings, where NX and NY are the number of sections along the chord and span of the wing respectively. The strength and position of the nascent vortex along the chord corresponding to the local e_ective angle of attack are evaluated from the residuals in viscous and potential ow, i.e. (Cl)visc– (Cl)potand (Cm)visc– (Cm)pot. Hence, the 2D airfoil viscous Cl– α and Cm– α is required as input (from experiment, numerical analysis or CFD). Aerodynamic characteristics and section distribution along span are predicted for 3D wings at post-stall angles of attack. Effect of initial conditions and existence of multiple solutions in the post-stall region is studied. Results are validated with experiment.