Prédiction du tremblement en écoulement transsonique

Under transonic flow conditions, the shock wave/turbulent boundary layer interaction and flow separation on the wing upper surface induce flow instabilities, designated as buffeting, which result in structure vibrations. This phenomenon can greatly influence the aerodynamic performance. These self-sustained flow excitations can produce enough energy to excite the structure. The objective of the present work is to correctly predict this unsteady phenomenon by using unsteady Navier-Stokes averaged equations with time dependent turbulence model based on suitable (k-ɛ) turbulent eddy viscosity model. The model used is based on the turbulent viscosity concept where the turbulent viscosity coefficient Cμ is related to local deformation and rotation rates. To validate this model, the flow over a flat plate at Mach number of 0.6 is calculated. The solution is in agreement with analytical results. The ONERA OAT15A transonic airfoil was chosen to describe buffet phenomena. Computational results show the ability of the present model to predict physical phenomena of the flow oscillations allowing a suitable description of the unsteady shock wave/boundary layer interaction. To cite this article: A. Kourta et al., C. R. Mecanique 333 (2005).