Abstract
Large eddy simulation of turbulent channel flow is carried out at Reτ values of 150 and 395. Mesh refinement effects are evaluated on conventional meshes, then local mesh refinement in streamwise direction is applied and investigated. The goal of the paper is to give proposal about the ideal position of the merging face and to show how many cells can be saved in this case without losing too much accuracy at both Reynolds numbers. The results are compared to DNS data.
Highlights
Channel flows are important reference cases of LES development, e.g. investigating different grid structures or developing new sub-grid scale models [12,13]
First is the relative difference of the friction Reynolds number (Eq (4)) compared to the reference, the second is the normalized mean square error, which is calculated as Eq (5)
Summary Wall-resolved large eddy simulations using Δx+=32...40, y+=1...1.5, Δz+=5...10 resolutions are performed for Reτ= 150 and 395 with very good agreement with DNS databases in literature
Summary
Channel flows are important reference cases of LES development, e.g. investigating different grid structures or developing new sub-grid scale models [12,13]. One technique is to use embedded or nested grids where a finer resolution grid is embedded (nested) into a zone of the coarser grid (e.g. near the wall in channels). This type of mesh refinement is used in [9,2], and [11]. Another technique involves a single mesh for the whole simulation domain and in one direction the resolution can be nonhomogeneous In this case the mesh zones are in direct interaction and the transition is ensured by some prism or distorted hexahedron cells.
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