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Session: High order methods
Session starts: Wednesday 19 June, 16:00
Presentation starts: 16:30
Room: Room 1.3

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Kristopher Davies (German Aerospace Center (DLR))
Michael Fehrs (German Aerospace Center (DLR))

Abstract:
The buffet phenomenon is commonly associated to the self-induced unsteady motion of a shock as a result of an interaction with the separated boundary layer on a wing in transonic conditions. Another unsteady flow phenomenon linked to separated flows is the so-called horizontal tailplane (HTP) buffet. Contrary to shock buffet, HTP buffet is an externally induced unsteadiness and is the consequence of turbulent structures convecting from the separated wing to the tailplane. This leads to fluctuations of the pressure distribution (buffet) and structural vibrations (buffeting) of the HTP. However, the dominating flow mechanisms and the critical frequency range causing HTP buffet are insufficiently understood. This work aims to study the flow interaction between the (separated) wing, its wake, and the tailplane in more detail. In this context, potential critical flight conditions in terms of HTP buffet need to be identified. This requires a variation of flow parameters, in particular the Mach number, Reynolds number, and angle of attack. Potentially, a multitude of flight conditions have to be considered, which requires a compromise between justifiable computing times and an adequate capturing of the most relevant unsteady flow effects. For this reason, this analysis is performed based on unsteady RANS simulations using a Reynolds Stress Model (RSM). This study is initially focussing on two-dimensional flows and is a prerequisite to understand similar effects on a more complex industrial configuration. In order to reproduce a realistic configuration of the wing and tailplane, the applied geometry is extracted based on the NASA Common Research Model (CRM) at a constant spanwise position.