Learning Forum

[Zari]

Hi,

I am Calculating a 2D fluid model (only Viscous model), and the residuals are as below, which it shows the epsilon is fluctuating.

Information of the model:Reynolds stress model, Quadric Pressure-strain, standard wall functions, default model constants

Solution methods: pressure-velocity: simple

Gradient: Green-Gauss node based

pressure: PRESTO!

momentum and viscosity and Re-stresses: second order Upwind

URFs:

Pressure: 0,3,

density: 0,5

Body forces: 1

Momentum: 0.6

Swirl velocity: 0.8

Turbulence kinetic energy, and, dissipation rate, and viscosity: 0.3

(I have reduced the turbulent residuals from 0.8 to 0.3 to see the effect on fluctuation of epsilon, which did not have an effect of fluctuation)

 

The mesh is a refined mesh, with an average element quality of 0.92 (stnd.dev: 0.24) and orthogonal quality 0.99 (stnd.dev: 0.05).

Do you have any suggestions for me to check the case and to improve the solution settings?

Regards,

Zari

 

[Rob]

Create a few monitor points and monitor (plot) velocity and k against iteration on these points. Also look at the results and try to understand what's going on: you may have picked up a transient in the flow field.