Improvement of Near Wall Behavior of Flow Field by Large Eddy Simulation

In order to be of use in engineering situations, LES models must be able to reproduce near-wall flows. We approach this by refining the mesh close to the walls and applying van driest type wall damping to resolve near wall zone and study of its effect on this region. To model sub grid scales, one equation model is applied which solves an additional transport equation for sub grid scale energy. The large scales which carry the main energy of the flow are resolved by directly integrating the filtered, time dependent Navier-Stokes equation. The technique is applied to fully developed turbulent flow in a channel for Reynolds number of 5600 based on channel widthd and bulk velocity and 180 based on friction velocity t u and channel half width with about 275000 grid points (65´ 65´ 65 in x, y, z). Number of turbulence statistics and flow profiles are computed and compared with the existing DNS data at the same Reynolds number. The agreement of computed skin friction coefficient, axial mean velocity profile and turbulent statistics e.g. axial root mean square velocity with DNS date are good.