Stochastic Modeling of Incident Gust Effects on Aerodynamic Lift

Abstract

The intrusive formulation of polynomial chaos expansion is implemented to determine uncertainty in aerodynamic loads on a rigid airfoil due to imprecise parameters that characterize an incoming gust. The results yield the sensitivity of the lift coefficient to variations in intensities and integral length scales of the gust fluctuations. The results show that lift coefficient fluctuations about the mean of each time step are affected primarily by the intensity ofthe fluctuations of the vertical velocity component, which should be expected. Next in order of importance is the integral length scale of the vertical velocity component. This implementation of the intrusive polynomial chaos expansion provides guidance for future efforts to quantify uncertain gust loads on micro air vehicles with higher fidelity models.