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Large-eddy simulations of turbulent channel flow at Reτ = 395 are performed using explicit filtering. Two different subfilter-scale models, the dynamic Smagorinsky mixed model and the dynamic global-coefficient mixed model, are formulated in accordance with the explicitly filtered governing equations. The use of explicit filtering separates the filtering operation from discretization, thereby producing a grid-independent solution. In explicit-filter large-eddy simulations, both the dynamic Smagorinsky mixed and the dynamic global-coefficient mixed subfilter-scale models are found to produce solutions close to the non-filtered direct numerical simulation data when explicit-filter widths in the streamwise and spanwise directions and at the center of the channel in the wall normal direction are about four times the grid spacings for direct numerical simulation. Solutions obtained using explicit-filter large-eddy simulation are compared with solutions obtained using implicit-filter large-eddy simulation in a range of filter and grid resolution. Explicit-filter large-eddy simulations performed on gradually refined grids with a fixed set of explicit-filter widths are found to produce grid-converged solutions for both models. Similarly in implicit-filter large-eddy simulation, predictive capabilities of subfilter-scale models in explicit-filter large-eddy simulation are found to be interfered with truncation errors when the ratio of the explicit-filter width to the grid spacing is small. [ABSTRACT FROM AUTHOR]

The governing equations for large-eddy simulation are derived from the application of a low-pass filter to the Navier-Stokes equations. It is often assumed that discrete operations performed on a particular grid act as an implicit filter, causing results to be sensitive to the mesh resolution. Alternatively, explicit filtering separates the filtering operation, and hence the resolved turbulence, from the underlying mesh distribution alleviating some of the grid sensitivities. We investigate the use of explicit filtering in large-eddy simulation in order to obtain numerical solutions that are grid independent. The convergence of simulations using a fixed filter width with varying mesh resolutions to a true large-eddy simulation solution is analyzed for a turbulent channel flow at Reτ=180, 395, and 640. By using explicit filtering, turbulent statistics and energy spectra are shown to be independent of the mesh resolution used. [ABSTRACT FROM AUTHOR]