Large eddy simulation of turbulent channel flow with buoyancy effects
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Structured grid finite volume formulations have been developed to solve the compressible Navier-Stokes equations for performing large eddy simulation of turbulent flows. These compressible formulations were developed using low Mach number preconditioning. Time marching was done with a coupled strongly implicit scheme. The discretization schemes were second-order accurate central difference and third-order accurate upwind and a comparison was made between two schemes. Validations were performed using turbulent compressible benchmark flows with low heat transfer. The results were compared to direct numerical simulation, experimental, and other large eddy simulation results. The large eddy simulations yielded excellent agreement with the direct numerical simulation and experimental results for incompressible turbulence. For the significant property variations, high heat transfer rate was imposed and the effects of buoyancy on the turbulent structures under stably, and unstably stratified flows were investigated. The effects of buoyancy were larger in the central region of channel where the largest Richardson number occurred. Despite the fact that the relative buoyancy production was small near the boundary walls, effects of buoyancy were observed.