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A high-resolved Large Eddy Simulation (LES) of the flow around an airfoil near stall has been achieved. We have observed that the laminar boundary layer undergoes a quick transition to turbulence in a Laminar Separation Bubble (LSB) close to the leading edge of the airfoil profile. The flow structures in this transitional flow region have been analysed and the transition mechanism seems accurately resolved. Hence, a reliable statistical data base of the transitional flow has been obtained. Then, the ability of the RANS method to reproduce the LES results, using a rough transition model, is analysed.

Institute for Technical Chemistry and Polymer Chemistry, University ofKarlsruhe, 76128 Karlsruhe, GermanySummary. The paper proposes two methods to couple an LES zone with a down-stream RANS zone. Both employ eddy viscosity models. One is based on a filtering–enrichment procedure, the other on an intermediate damping zone. Simulations ofdeveloped plane channel flow at

The aim of the present work is to predict and describe the boundary layer transition process influenced by an incoming upstream turbulent wake generated by a moving cylinder for a subsonic blade turbine configuration. High-resolution Large-Eddy Simulation type computations have been carried out for the T106 low-pressure blade turbine at Mach number of 0.1 and chord based Reynolds number of 1.6 105 and have been compared with experiments.

A Large Eddy Simulation (LES) of a turbulent flow over the A-airfoil near stall at a chord Reynolds number of 2.1 × 106 is performed and compared to windtunnel experiments. This configuration still constitutes a challenging test case for Reynolds Averaged Navier-Stokes (RANS) simulation and LES due to the complexity of the suction side boundary layer: an adverse pressure gradient creates successively a laminar separation bubble, a turbulent reattachment and a separation near the trailing edge. To handle this high Reynolds number flow with LES on available supercomputers, a local mesh refinement technology and a low dissipative scheme are developed. It appears that the computed mean and fluctuating velocity profiles compare reasonably well with experimental measurements.

The aim of the present work is to predict and describe the transition process and its interaction with the wake dynamics for a subsonic blade turbine configuration. High-resolution Large-Eddy Simulation type computations have been carried out for the T106 low-pressure blade turbine at Mach number of 0.1 and chord Reynolds number of 1.6 105 and have been compared with experiments.