Flutter Predictions with a Reduced-Order Aeroelastic Model

Abstract

Reduced-order aeroelastic models have been formulated to approximate the flow dynamics with a low-dimensional set of eigenmodes, utilizing the method of proper orthogonal decomposition. The reduced-order flow model is coupled to a modal representation of the structural dynamics, forming a small set of ordinary differential equations that comprise the aeroelastic model. The eigenvalues of the system of linear equations determine aeroelastic response. The physics-based, reduced-order model is constructed with data from a relatively small set aeroelastic CFD simulations. The method was evaluated by comparing predictions of the flutter boundary of an AGARD 445.6 wing to a boundary computed with data from much larger sets of aeroelastic CFD simulations that include the on-design runs used to construct the model and off-design runs that were not used during model construction. The correspondence between each reduced-order model and its high-dimensional, parent model is reasonably close, and the difference in size between the two is four orders of magnitude with a commensurate reduction in computational overhead.