Numerical Exploration of the Unsteady Sonic Buffet of OAT15A Airfoil

Abstract: Self-sustained oscillations of shock waves on airfoils may arise when specific combinations of transonic Mach numbers (M?) and angles of attack (AoAs) interact with the shock and the separated boundary layer. The phenomenon is typically known as shock buffet. It is widely known that these oscillations impact the aircraft performance significantly and lead to a loss in the stability and efficiency of the aircraft. The reason behind the shock formation is the expansion of air at higher subsonic regimes (transonic regime), leading to sonic speeds at specific points on the airfoil. The current work focuses on investigating the shock oscillations on the top surface of the supercritical OAT15A airfoil across different angles of attack using numerical simulations. The analysis employs ANSYS Fluent and the open-source package OpenFOAM to examine the shock buffet effects on the performance, namely the pressure coefficient. Additionally, this study highlights key differences between steady-state and transient solutions. Keywords: Transonic Buffet, Supercritical Airfoil, OpenFOAM, Shock wave