ZDES and URANS Simulations of 3D Transonic Buffet Over Infinite Swept Wings

This paper presents a study of transonic buffet over three-dimensional infinite swept wings. These configurations consist of the extrusion of an ONERA OALT25 airfoil with periodic boundary conditions in the spanwise direction. Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations are first performed to assess the effect of the sweep angle. Spanwise flow structures are observed on these essentially 2D or 2.5D configurations, forming what has been named buffet cells. The 3D buffet frequency is correlated with the wavelength of these cells and the sweep angle. Then, Zonal Detached Eddy Simulations (ZDES) are carried out over small span and large span wings to provide numerical validation to the URANS simulations. These simulations are used to assess the capacity of hybrid RANS-LES methods to model the 3D effects involved in transonic buffet. At last, these simulations will provide insights into the complex physics involved in transonic buffet.