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Old   October 31, 2009, 10:28
Default continuity diverging problem
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Mijin Kim
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Hi, guys
I am solving non-newtonian blood flow with carreau model.
Because I couldn't understand what the "Activation Energy" in ""property panel >> viscousity >> carreau "" I made my UDF code for carreau model
, which is below

#define mu_inf 0.00345
#define rho 1050
#define mu0 0.056
#define n 0.3568
#define K 3.133

DEFINE_PROPERTY(carreau_viscosity,c,t){
real mu_carr, gamma;
real n1 =(n-1)/2;

gamma = C_STRAIN_RATE_MAG(c,t);
mu_carr = mu_inf +(mu0 - mu_inf)*pow((1+pow(K,2)*pow(gamma,2)), n1 );
return mu_carr;
}


First, I solved the case with constant viscosity, mu_inf=0.003465
and then, only changed fluid viscosity by udf carreau model and reiterated the case.

Here, I got some problems.
all of the residuals , espcially the continuity, diverge.
I cannot notice what the problem is, And i need ur help!!

Is there anyone who can let me know How can i get the right solution?
Please help me,,,
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carreau, diverge, non-newtonian, udf, viscosity

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