Numerical investigation of effect of variable viscosity on decaying turbulence flow field using DNS technique

摘要

In recent years, significant amount of research has been performed in the area of turbulent mixing flow using Direct Numerical Simulation (DNS). Direct Numerical SImulation has been used to understand the physics of moderate-Reynolds-number flows as well as to investigate mixing characteristics in turbulent mixing flows. In this study a DNS model is used to investigate the effect of variable viscosity on the evolution of scalar fields of different initial integral scales in decaying, homogeneous, isotropic turbulence. The model is based on three-dimensional incompressible Navier-Stokes equations together with a scalar equation. The computational solution is based on sixth order accurate COmpact Finite Difference schemes to discretize t he convective and diffusive terms and using an algorithm based on the Fractional Step Method.