CFD Online Discussion Forums - How to make it work on parallel mode

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How to make it work on parallel mode

This UDF works perfectly in serial mode,

/************************************************** ********************
UDF to calculate temperature at outlet and use it as a inlet temperature (for closed loop )

************************************************** *********************/
#include "udf.h"
#include "prf.h"
#include "para.h"

real tavg, Tavg;
DEFINE_EXECUTE_AT_END(average_temp)
{
#if !RP_HOST
real temper = 0.0;
real area = 0.0;
real area_tot = 0.0;

Domain *d;
face_t f;
real A[ND_ND];

int zone_ID;
int ID = 7; /*outlet boundary wall*/
Thread *t;
d = Get_Domain(1);
t = Lookup_Thread(d,ID);
tavg = 0.0;
Tavg = 0.0;

begin_f_loop(f,t)
{
F_AREA(A,f,t);
area = NV_MAG(A);
area_tot += area;
temper = F_T(f,t);
tavg += temper*area;
}
end_f_loop(f,t)
Tavg = tavg/=area_tot;

printf("Tavg = %g Total_area = %g\n",Tavg,area_tot);
#endif
}

#include "udf.h"
DEFINE_PROFILE(inlet_temp,t,i)
{
#if !RP_HOST
face_t f;
begin_f_loop(f,t)
{
F_PROFILE(f,t,i) = tavg;
}
end_f_loop(f,t)
/* printf("Inlet_temperature = %g\n",tavg); */
#endif
}

But when i try to compile it,

I am getting an error

Tavg = -nan(ind) Total_area = 0
Tavg = -nan(ind) Total_area = 0
Tavg = -nan(ind) Total_area = 0
Tavg = 295 Total_area = 7.83488e-05
Tavg = -nan(ind) Total_area = 0
Tavg = -nan(ind) Total_area = 0

I need help on how to use PRF_GSUM1(....)

Can you not use periodic BC to couple inlet and outlet?

Code:

/************************************************** ********************

UDF to calculate temperature at outlet and use it as a inlet temperature (for closed loop )



************************************************** *********************/

#include "udf.h"

#include "prf.h"

#include "para.h"



real tavg, Tavg;

DEFINE_EXECUTE_AT_END(average_temp)

{

real temper = 0.0;

real area = 0.0;

real area_tot = 0.0;



Domain *d;

face_t f;

real A[ND_ND];



int zone_ID;

int ID = 7; /*outlet boundary wall*/

Thread *t;

d = Get_Domain(1);

t = Lookup_Thread(d,ID);

tavg = 0.0;

Tavg = 0.0;



begin_f_loop(f,t)

{

F_AREA(A,f,t);

area = NV_MAG(A);

area_tot += area;

temper = F_T(f,t);

tavg += temper*area;

}

end_f_loop(f,t)

# if RP_NODE /* Perform node synchronized actions here; Does nothing in Serial */

area_tot = PRF_GRSUM1(area_tot);

tavg = PRF_GRSUM1(tavg);

# endif /* RP_NODE */

Tavg = tavg/=area_tot;

Message0("Tavg = %g Total_area = %g\n",Tavg,area_tot);

}



DEFINE_PROFILE(inlet_temp,t,i)

{

face_t f;

begin_f_loop(f,t)

{

F_PROFILE(f,t,i) = tavg;

}

end_f_loop(f,t)



}

Dear Tkachenko,

Yes, Periodic BC works perfectly but I also have to use outlet temperature to calculate thermal properties.