Large Eddy Simulation of the Turbulent Flow around a Circular Cylinder with Non-eddy Viscosity SGS model

Abstract

The rapid development of the modern computer in speed and memory provides a powerful tool to investigate the turbulence. Recent direct numerical simulation (DNS) of the Navier-Stokes equation has demonstrated its capability to describe the details of the turbulent flow. However, the ratio of the largest scale to the smallest scale of vortexes in turbulent flow increases with the Reynolds number of the flow rapidly, hence the scale of the computational domain must be larger than the largest scale and the mesh scale should be less than or at least equal to the scale of the smallest vortex,. Then the mesh number is very large and the required memory of computer will be so enormous to exceed the limit of the recent supercomputer even if the Reynolds number is moderate. As a compromise method, the large eddy simulation(LES) emerges as the times, in which the vortexes with mesh-like scale can be described and the influence of the movement with the smaller scale to the simulated movement with large scale is achieved through the subgrid scale modeling. When the mesh scale is small sufficiently, the major performance and details of the turbulence can be displayed.