Large Eddy Simulation of a Turbulent Flow Past a symmetric backward-facing steps: a sensitivity analysis

Författare: Duwig, C., Salewski, M., Fuchs, L.F.
Dokumenttyp: Konferens
Tillstånd: Publicerad
Volym: AIAA 45th   AIAA-2007-0916
År: 2007


Large Eddy Simulation is used to study the flow behind a pair of symmetric backward facing steps. As reported in the literature, the flow exhibits an asymmetric pattern characterized by the deflection of the jet toward of the walls. The LES results are compared to LDA measurements showing the ability of the present numerical tool to capture the complex features of the flow. Furthermore, a sensitivity study is conducted in order to assess the influence of the grid resolution, inflow boundary, channel width (aspect ratio Ah) and step size (h) on the flow field. The flow was found to be weakly sensitive to the grid, assuring the quality of the simulation results. The inflow boundary influences the results only marginally unless low frequency fluctuations are applied. In this case, the flow field recovers symmetry with suppression of the jet bending. The jet bending has also been shown to increase with the step size h and to reduce with increasing Ah.