Uncertainty Quantification of a Flapping Airfoil with Stochastic Velocity Deviations Using the Response Surface Method

ABSTRACT

A practical flapping wing micro air vehicle should have ability to withstand stochastic deviations of flight velocities. To design a flapping airfoil with this ability, it is necessary to evaluate the impacts of velocity deviations on the flapping performances numerically or analytically. In this paper, the responses of the time-averaged thrust coefficient and the propulsive efficiency with respect to a stochastic flight velocity deviation under Gauss distribution are numerically investigated using a classic Monte Carlo method. The response surface method is employed to surrogate the high fidelity CFD model to save computational cost. It is observed that both of the time-averaged thrust coefficient and the propulsive efficiency obey a Gauss-like but not the exact Gauss distribution. The effect caused by the velocity deviation on the timeaveraged thrust coefficient is larger than the one on the propulsive efficiency.