Two-Dimensional and Three-Dimensional Buffet Flows Characterization and Their Role in Aeroelastic Instabilities

Shock buffet is an aerodynamic instability characterized by self-sustained shock oscillations, which occurs at transonic Mach numbers and moderate angles-of-attack on both airfoil (two-dimensional, 2D) and wing (three-dimensional, 3D) configurations. The variation of the aerodynamic coefficients degrades handling qualities and aerodynamic performance, eventually limiting flight envelopes. Furthermore, the shock oscillations occur at frequencies close to the natural modes of wings, thus, might lead to unstable structural interactions.

Although many studies were performed on 2D configurations, the understanding of the fundamental mechanism of the rigid 3D shock buffet and its interaction with elastic wing structures is still limited.  A better understanding of these two issues is essential for structural design of transonic aircraft and can support the development of control strategies for buffet suppression in realistic flight configurations.

The current study presents a computational investigation using Unsteady Reynolds-Averaged Navier-Stokes simulations and modal analysis of the shock buffet on 3D configurations, its distinction from 2D shock buffet, and the fluid-structure interaction between the 3D shock buffet flow and wing elasticity in finite wings.