Flutter Analysis of the Benchmark Supercritical Wing at Moderate Angles of Attack

The paper presents flutter analyses of the Benchmark Supercritical Wing, at moderate angles of attack, performed as part of the Third Aeroelastic Prediction Workshop. Aeroelastic simulations of the pitch and plunge spring-suspended wing were performed using the EZAir flow solver at an ambient Mach number of 0.8, angles of attack ranging from one to five degrees, and various dynamic pressure values. Flutter onset was detected and compared with experimental data, where available. The focus of the study was threefold: 1) Predicting flutter in a computationally efficient manner by fitting a linear dynamic model to responses at pre-flutter conditions and extrapolating a stability parameter, 2) Studying the angle of attack effect on flutter onset and mechanism at this transonic Mach number, and 3) Studying the possible relation between shock buffet and flutter, and the fluid-structure interaction mechanism. Simulations indicate that as the angle of attack increases, shock buffet occurs, the flutter-onset dynamic pressure decreases significantly, and the flutter mechanism changes from two degrees of freedom to single-degree-of-freedom pitch oscillations.