cfx time scale control
 

Hi again

I am modelling a double facade in cfx. My first model had a uniform grid of only hexas, and had been designed in workbench. In that model I had apply a time scale control of type "Local Tine Scale Factor" and with value of 0.2 and I hade also model it with buoyancy. I hade some successful runs.

Now I have made a new grid with inflation in ICEM, again only hexas. The grid has an inflation of 1.2 logarithmic on the walls. I am trying to run this mesh with the same setting on cfx, but it does not converge. I tried all the scale control options but still nothing. The mesh has a very good quality.

Could anyone suggest me a time scale control

Thank you

Re: cfx time scale control
 

Hi,

For some types of simulations an expansion ratio of 1.2 is too much. Try decreasing it.

The CFX documentation has extensive discussions about how to obtain convergence.

Glenn Horrocks

Re: cfx time scale control
 

You might try using a physical timestep. I often get good convergence using a timestep about 1/3 of the advection time of my domain.