[I-mech]

I would really appreciate if somebody take a look in the UDF and give me some advices.

I'm trying to define the temperature at the Pressure Inlet (ID=9) from the temperature at Pressure Outlet (ID=10).
So i've written an UDF that in order:
1. defines temperature dependent viscosity;
2. calculates massflow at outlet;
3. calculates massflow at inlet;
4. calculates averaged temperature at outlet;
5. defines the temperature for the pressure inlet.

At the beginning of the solution the following error occurs:

iter continuity x-velocity y-velocity z-velocity energy time/iter

Error:
C:\PROGRA~1\ANSYSI~1\v145\fluent\fluent14.5.0\win6 4\3d\fl1450s.exe received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: #f

Viscosity UDF works for sure so i've tried to run the simulation only with the following UDF:

/************************************************** *******************
Define scalars for following operations
************************************************** ********************/

real flowout_tot;
real flowin_tot;
real tavg_tot;


/************************************************** *******************
UDF measuring mass flow at pressure outlet ID 10
************************************************** ********************/

DEFINE_EXECUTE_AT_END(measure_flow_out)
{
Domain *d;

real flowout;
cell_t c;
Thread *tout;
face_t f;
d = Get_Domain(1);
tout = Lookup_Thread(d,10);

begin_f_loop(f,tout)
{
flowout+=F_FLUX(f,tout);
}
end_f_loop(f,tout)
printf("MASS Flow Rate Out: %g\n",flowout);
flowout_tot = flowout;
flowout = 0.;
}

I have seen in other threads something very similar so i really don't understand where is the problem.
Thanks in advice

[I-mech]

Looking the UDF row by row i've found there was a Get_Domain_(11) instead of Get_Domain(1).
Now the UDF is working.

I've attached the complete UDF for those who are looking for something similar, and for those who have useful advice to give me.

/************************************************** *******************
UDF for Temperature dependent Dynamic Viscosity
************************************************** ********************/
#include "udf.h"
#include "math.h"
DEFINE_PROPERTY(cell_viscosity,cell,thread)
{
real mu_lam;
real temp = C_T(cell,thread);
{
mu_lam=0.0000631*pow(10,3.722*pow(1+(temp-273)/(135),-1.102));
return mu_lam;
}
}

/************************************************** *******************
Define scalars for following operations
************************************************** ********************/

real flowout_tot;
real flowin_tot;
real tavg_tot;


/************************************************** *******************
UDF measuring mass flow at pressure outlet ID 10
************************************************** ********************/

DEFINE_EXECUTE_AT_END(measure_flow_out)
{
Domain *d;

real flowout;
cell_t c;
Thread *tout;
face_t f;
d = Get_Domain(1);
tout = Lookup_Thread(d,10);

begin_f_loop(f,tout)
{
flowout+=F_FLUX(f,tout);
}
end_f_loop(f,tout)
printf("MASS Flow Rate Out: %g\n",flowout);
flowout_tot = flowout;
flowout = 0.;
}

/************************************************** *******************
UDF measuring mass flow at pressure inlet ID 9
************************************************** ********************/

DEFINE_EXECUTE_AT_END(measure_flow_in)
{
Domain *d;

real flowin;
cell_t c;
Thread *tin;
face_t f;
d = Get_Domain(1);
tin = Lookup_Thread(d,9);

begin_f_loop(f,tin)
{
flowin+=F_FLUX(f,tin);
}
end_f_loop(f,tin)
printf("MASS Flow Rate In: %g\n",flowin);
flowin_tot = flowin;
flowin = 0.;
}

/************************************************** *******************
UDF measuring Temperature at pressure outlet ID 10
************************************************** ********************/

DEFINE_EXECUTE_AT_END(Temp_outlet)
{
Domain *d;

real Temp_t;
real area;
real area_tot;
real tavg;
real A[ND_ND];
Thread *t;
face_t f;
d=Get_Domain(1);

t=Lookup_Thread(d,10);

tavg=0;
area_tot=0;
begin_f_loop(f,t)
{
F_AREA(A,f,t);
area_tot += NV_MAG(A);
tavg += F_T(f,t)*NV_MAG(A);
}
end_f_loop(f,t)
tavg /= area_tot;
tavg_tot=tavg;
printf("Averaged Temperature at Pressure Outlet: %g\n",tavg_tot);
}

/************************************************** *******************
UDF settting temperature at pressure inlet ID 9
************************************************** ********************/

DEFINE_PROFILE(temp_mixing,t,i)
{
real lambda=1;
real temp_mix;
real temp_supply=323;
face_t f;

if (ABS(flowin_tot) == 0)

temp_mix = temp_supply;

else

temp_mix = (lambda*ABS(flowout_tot)*(tavg_tot)+(ABS(flowin_to t)-lambda*ABS(flowout_tot))*temp_supply)/(ABS(flowin_tot));

begin_f_loop(f,t)
{
F_PROFILE(f,t,i) = temp_mix;
}
end_f_loop(f,t)
printf("Adjusted temperature: %f\n",temp_mix);
}