ding in the other two. This technique permits a fine grid to be embedded near the wall without placing a large A B-spline based numerical method on a zonal embedded grid has been developed. The method is aimed at reducing the computa-number of grid points in the outer layers. As a result, the tional requirements for large eddy simulations (LES) and direct nutotal number of grid points is reduced which leads to savmerical simulations (DNS) of wall-bounded turbulent flows. The ings in CPU time and memory.
objective is to reduce the number of grid points required to resolve A pacing item for large eddy simulations of high the near-wall eddies without placing a large number of grid points Reynolds number flows of engineering interest is an accuin the outer layers. DNS and LES calculations of a turbulent channel rate treatment of the near-wall turbulence structures. As flow were performed on a grid with a zone near the wall that was refined in all three directions. The results from the zonal grid calculapointed out by Moin and Jimene ยดz [1], the near wall structions show good agreement with previously published numerical tures are the important large eddies, so they cannot be and experimental results obtained for the same flow conditions. treated accurately with subgrid scale parameterizations. The zonal grid calculations required only a fraction of the CPU time Instead, they need to be resolved or completely modeled required for the single zone grid calculation with the same nearwith dynamic wall functions [2][3]. An efficient computawall grid density. In addition, the memory requirements for the zonal grid calculations are significantly reduced. แฎ 1996 Academic Press, Inc. tion of these structures can be achieved with zonal grids. This is an important step in computation of higher Reynolds number flows of aerodynamic interest.