CONVERGE™ Minimizes Artificial Viscosity to Produce Highly Accurate Results
It is well known that when solving the discretized Navier Stokes equations, an additional diffusion is present which enhances the diffusivity. This extra diffusion, called “numerical viscosity,” is a non-physical artifact of CFD and should be considered when analyzing CFD results.
One way to test the level of numerical viscosity in a CFD solver is to simulate the mixing of two fluids (with different temperatures) and set the fluid diffusion coefficients to zero. For such a conceptualized case, the theoretical temperature profile should contain a discontinuity. If the CFD solution shows any smearing, then we can safely assert that the numerical scheme contains numerical diffusion.
Learn more about minimizing numerical diffusion with CONVERGE™ in this paper: Numerical Viscosity.