[alanhuang]

Hello everyone,

I am dealing with a type of non-Newtonian fluid that is similar with power-law fluid.
Here is the code:

#include "udf.h"
DEFINE_PROPERTY(cell_viscosity, cell, thread)
{
real visco;
real mu;
real R;
R = C_STRAIN_RATE_MAG(cell,thread);
mu = 0.14*2.8284*pow(R,-0.56)-0.0018284;
if(mu > 0.001)
visco = mu;
else
visco = 0.001;
return visco;
}


The code is very simple but it shows"Divergence detected in AMG solver:x momentum Error" when it was used.

I thought it was the problem of initial viscosity, so I set the initial viscosity to be 0.001 but it doesn't work.

I am going to calculate the thermally fully developed nusselt number with B.C. of constant heat flux by using periodic method, can anyone give suggestions?

I would appreciate any kind of help.

Thank you,

Alan

[alanhuang]

At last i set the limitation of max viscosity, and it works.
Thanks for everyone who has reviewed this