Large Eddy Simulation of Turbulent Channel Flow Using Smagorinsky Model and Effects of Smagorinsky Constants
M. Ashraf Uddin
Department of Mathematics, Shahjalal University of Science and Technology, Sylhet, Bangladesh.
M. Saiful Islam Mallik *
Department of Mathematics, Shahjalal University of Science and Technology, Sylhet, Bangladesh and Department of Arts and Sciences, Ahsanullah University of Science and Technology, Dhaka, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
A large eddy simulation (LES) of a turbulent channel flow is performed by using the Smagorinsky subgrid scale model and the effects of Smagorinsky constants in LES are discussed. The computation is performed in the domain of 2πδ x 2δ x πδ with 32 x 64 x 32 grid points at a Reynolds number Reτ = 590 based on the channel half width, δ and wall shear velocity, {C}{C}{C}{C}uτ. The performance of the Smagorinsky model is tested in LES for three values of Smagorinsky constant, {C}{C}{C}{C}CS = 0.065, 0.1 and 0.13, and for all three cases the computed essential turbulence statistics of the flow field are compared with Direct Numerical Simulation (DNS) data. Comparing the results with those from DNS data throughout the whole calculation domain we have found that turbulence statistics for CS = 0.065 show reasonable agreement with the DNS data. Agreements as well as discrepancies are discussed. The behavior of the flow structures in the computed flow field has also been discussed.
Keywords: Large eddy simulation, turbulent channel flow, smagorinsky constant, staggered grid.