Numerical Investigation of Vortex-Breakdown Induced Tail Buffet on the DLR-F23 Configuration with Vertical Tail

Abstract

In this study, the vortex-dominated flow field of the DLR-F23-T hybrid-delta-wing configuration with a vertical tail is investigated numerically. The focus of this work is on the investigation of the vortex breakdown and the aerodynamic excitation of the vertical tail (buffet) at a Mach number of 0.55 and medium to high angles of attack. High pressure fluctuations with distinct frequency contents characterize the flow field downstream of the vortex breakdown and are responsible for the excitation of the vertical tail. URANS simulations and Improved Delayed Detached Eddy Simulations (IDDES) are performed for one selected case at an angle of attack of 24°. The frequency analysis of the root bending moment shows a strong excitation of the vertical tail at a reduced frequency of k=1, which can be assigned to the helical mode instability of the vortex breakdown flow.