CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Eulerian Modeling: Frictional Viscosity Help (

meangreen July 8, 2009 14:46

Eulerian Modeling: Frictional Viscosity Help
Dear All,
I tried to make a UDF to mimic the frictional viscosity (Schaeffer) coded inside of fluent, but I was not able to do it. I know fluent sets a limit of 10^5 for the frictional viscosity, but I dont know how fluent deals with the frictional viscosity when the deviatoric strain rate is zero (since this is in the denominator or the frictional viscosity). I am simulating a bed of particles interacting with a jet of gas, so initially the particles aren't moving and I am having trouble with my UDF finding a way to properly limit the frictional viscosity. I tried using something where if deviatoric strain < 10^-12 then frictional viscosity = (Pf*sin(phi))/(solidsvof*10^-12). However, when I did this I still could not repeat the simulation results had found. Even with a higher limit on the frictional viscosity, the bed in my case was more liquid like than the fluent case.

Can anyone help? I have been banging my head against this problem for weeks. Let me know if you need more information.


:confused::confused::confused::confused::confused: :confused::confused::confused::confused:

All times are GMT -4. The time now is 13:51.