[AminRa]

Hi everyone,
I'm solving a non-Newtonian flow problem in fluent. I wrote a udf for different boundary conditions and viscosity model. Unfortunately, when I'm using all of them, I cannot get solution (floating point at start). Interesting enough, when I use constant viscosity, it works perfectly. then after 10 or 20 iteration I select my viscosity model in material>Fluid and it converges. Convergence is still slow. So I was looking for a way to get the iteration number in udf and apply my viscosity model slowly after every iteration.

my model:
-non Newtonian fluid flow with heat transfer (viscous dissipation)
- both variable (udf defined) velocity and temperature profile at inlet
- viscosity model: Carreau-Yasuda with temperature dependency