[felipe2308]

Hello everyone.
I am currently working on a porous zone problem. I want to ask for help on how to write a UDF for an energy source term that depends on a density that is also calculated with a UDF.
This depends on a temperature change having a reference temperature of 270 k and using a T (c,t) and the passage of time (t)
The function would look like this:
source=rho*CP* ∆T/∆t

I would greatly appreciate your help. I am new to C programming language and creating UDFs

[AlexanderZ]

use both define_property and define_source macros in udf
inside define_property define density dependence
inside define_source use this source=rho*CP* ∆T/∆t

[felipe2308]

I have this udf but I don't know if it is correctly defined.
I can interpret it but when I solve it i get an error

CODE:
#include "udf.h"

DEFINE_PROPERTY (cell_density,c,t)
{
Thread *t;
cell_t c;
real rho;
real temp = C_T (c,t);
if (temp <=295 && temp>=270)
rho = (-708.84*(temp*temp)) + (9666.4*temp) + 2e+06;
else
rho = (5746.4*(temp*temp)) - (61528*temp) + 1e+06;
return rho;
C_UDMI (c,t,0) = rho;
}

DEFINE_SOURCE (energy_source, c, t, dS, eqn)
{
real source;
real T = CURRENT_TIME;
real tempref = 270;
real temp = C_T (c,t);
source = C_UDMI (c,t,0)*((temp-tempref)/(T));
dS[eqn] = 0;
return source;
}

error:
Error: received a fatal signal (Segmentation fault).
Error Object: #f

Thanks for your help
best regards

[AlexanderZ]

For future:
compile code (not interpret) and read log, fix errors

#include "udf.h" 

DEFINE_PROPERTY(cell_density,c,t)
{
real rho,temp;
temp = C_T(c,t);
if (temp <=295 && temp>=270)
rho = (-708.84*(temp*temp)) + (9666.4*temp) + 2E06;
else
rho = (5746.4*(temp*temp)) - (61528*temp) + 1E06;
return rho;
}

DEFINE_SOURCE(energy_source, c, t, dS, eqn)
{
real source,T,temp,tempref;
T = CURRENT_TIME;
tempref = 270;
temp = C_T (c,t);
source = C_R(c,t)*((temp-tempref)/(T));
dS[eqn] = 0;
return source;
}