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Old   June 6, 2011, 23:33
Default udf error
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I am new in using udf in fluent. I wrote udf to define properties of individual materials and their mixture. Some examples are shown as below:

DEFINE_PROPERTY(nitrous_oxide_viscosity, c, t)
real E; /* self-defined variable for convenience */
real mu; /* calculated viscosity in unit kg/m.s */
real T = C_T(c,t); /* temperature in unit kelvin, K */
const real A = 0.4733; /* dimensionless regression coeficient */
const real B = 21.8; /* dimensionless regression coeficient */
const real C = -0.004923; /* dimensionless regression coeficient */
const real D = -0.000004274; /* dimensionless regression coeficient */
E = A + B/T + C*T + D*T*T; /* self-defined variable for convenience */
mu = 0.001*pow(10, E); /* calculated viscosity in unit kg/m.s */
return mu; /* calculated viscosity in unit kg/m.s */

DEFINE_PROPERTY(mixture_thermal_conductivity, c, t)
real sum = 0.0;
int i;
Material *sp;
real ktc;
Property *prop;
mixture_species_loop(THREAD_MATERIAL(t), sp, i)
ktc = generic_property(c, t, prop, PROP_ktc, C_T(c,t));
sum += C_YI(c,t,i)*ktc;
return sum;

Error appears for simulation. 1 1.#QNBe+00 is shown for all residuals.

I did a check and found that udf causing the error. Can pls help me to check is there any mistake to my udf? I totally do not know what wrong is going on. Pls help.

Thanks for help.
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Old   November 15, 2013, 09:51
Join Date: Jun 2013
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Hello raymond
Could you sloved the problem associated with UDF?
I encountered with the same problem in running of species transport UDF. all of iterations are converged but donot display the residuals. in addition to .QNBe+00 is appered in the iterations.
Can you help me?

Last edited by mehdimoradi.; November 16, 2013 at 12:20.
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