Goéric Daeninck

Simulation of three-dimensional bluff-body flows using vortex methods: from direct numerical simulation towards large-eddy simulation modelling

Recent contributions to the three-dimensional vortex method for bluff-body flows are presented. The numerical method a vortex method combined with a boundary element method is briefly reviewed. It is applied to direct numerical simulation of the flow past a sphere (Re = 300 and 1000). The on-going work to extend the method towards vortex-based large-eddy simulation for high Reynolds number flows is also presented. Preliminary results for the flow past a hemisphere are discussed.

On Near-Wall Dynamic Coupling of LES With RANS Turbulence Models

In this paper, the RANS/LES coupling formulation proposed in [1–3] is adapted for various RANS turbulence models. In that formulation, the LES subgrid-scale eddy-viscosity is replaced in the near-wall region with a RANS eddy-viscosity dynamically corrected with the resolved turbulent stress. The RANS eddy-viscosity is first obtained from precomputed tables. To further generalize the approach, RANS turbulence model equations (for Spalart-Allmaras and k-ω) are then solved simultaneously with the LES. Detailed results are presented for channel flow at Reτ = 395 and compared to traditional LES. The method is then applied to a serpentine passage and compared with DNS computations [4] at Reτ = 180.Copyright

Simulation of vehicle aerodynamics using a vortex element method

Recent developments of the 3-D Lagrangian vortex element method for bluff body flows are presented. In this approach attached boundary layer regions are modelled using infinitely thin vortex sheets while Lagrangian vortex elements are used for the separation regions and the wake. Preliminary results for the flow past a simplified generic truck geometry are presented. Further developments, aimed at the development of a hybrid Eulerian-Lagrangian solver, are briefly introduced.