Investigating the noise sources of the transonic RAE 2822 airfoil

Abstract

Abstract: A compressible Large Eddy Simulation is performed on the transonic RAE 2822 airfoil, and compared to the baseline simulation of Koch et al. (28th AIAA/CEAS Aeroacoustics Conference, paper AIAA 2022–2816) in order to highlight the main noise source mechanisms. The new simulation employs a new mesh which eliminates a jump in the airfoil surface mesh, located in the supersonic laminar boundary layer region of the suction side. This jump induced some hydrodynamic instability in the suction side boundary layer of the baseline simulation, potentially emitting noise at high-frequencies. The new results show that these instabilities are significantly damped when employing the new refined mesh and are consequently very sensitive to the grid quality. Nonetheless, the acoustic response of the airfoil, calculated using the Ffowcs Williams and Hawkings analogy in its solid formulation, remains similar to the baseline, with a highfrequency hump appearing between 30 and 40 kHz. This shows that this hump is not caused by the hydrodynamic instabilities, therefore confirming the grid independence of the acoustic results.Communication présentée lors du congrès international tenu conjointement par Canadian Society for Mechanical Engineering (CSME) et Computational Fluid Dynamics Society of Canada (CFD Canada), à l’Université de Sherbrooke (Québec), du 28 au 31 mai 2023