Wake Tail Plane Interactions for a Tandem Wing Configuration in High-Speed Stall Conditions

In this work, wake-tail plane interactions are investigated for a tandem wing configuration in buffet conditions using hybrid RANS/LES simulations with the Automated Zonal Detached Eddy Simulation (AZDES) method. The analyzed configuration consists of two untapered and unswept wing segments, representative of a wing-tail plane configuration. The shock oscillation on the front wing segment and the development of its turbulent wake are characterized, including a spectral analysis of the pressure and velocity fluctuations in the wake and a modal analysis of the flow field applying Proper Orthogonal Decomposition (POD). The impact of the wake on the aerodynamics and loads of the rear wing segment is then studied, with a spectral analysis of its lift and surface pressure oscillations. Finally, the influence of the position and the incidence angle of the rear wing segment are investigated. For the considered flow conditions, 2D buffet is present on the front wing segment. During the downstream movement of the shock, the amount of separation reaches its minimum and small vortices are present in the wake. During the upstream movement of the shock, the amount of separation is at its maximum and larger turbulent structures are present together with high fluctuation levels of velocity and pressure. A distinct peak can be associated with the meandering motion of wake vortices, identified by means of a modal analysis of the flow field using Proper Orthogonal Decomposition. The impingement of the wake causes a strong variation of the loading of the rear wing segment. A comparably low-frequent oscillation of the lift coefficient, attributed to the change of intensity of the downwash caused by the front segment, can be distinguished from fluctuations of high frequency that are caused by the impingement of the turbulent structures in the wake.