[Prabhumsrit]

I'm trying to write a UDF to give a velocity at an interior face (Nozzle Exit). When I am trying to compiling following error was coming

Error: received a fatal signal (Segmentation fault).

UDF file


#include "udf.h"
#include "mem.h"
#include "math.h"


DEFINE_EXECUTE_AT_END(Velocity)
{
Domain *d;
face_t f;
cell_t c0, c1 = -1;
Thread *t, *t0, *t1 = NULL;
real NV_VEC(psi_vec), NV_VEC(A), flux = 0.0;
c0 = F_C0(f,t);
t0 = F_C0_THREAD(f,t);
F_AREA(A, f, t);
d = Get_Domain(1);
t= Lookup_Thread(d, 2);
begin_c_loop

{
c1 = F_C1(f,t); /* Get cell on other side of face */
t1 = F_C1_THREAD(f,t);
NV_DS(psi_vec, =, C_U(c0,t0),C_V(c0,t0),C_W(c0,t0);
NV_DS(psi_vec, +=, C_U(c1,t1),C_V(c1,t1),C_W(c1,t1);

}
end_f_loop (f, t)
}

Please find the attachement file of boundary condition


Or

Suggest me to write the UDF code to calculate interior face velocity.

This is very useful for my project .

advance Thanks for fast reply.

[AlexanderZ]

in your code:

begin_c_loop
but
end_f_loop (f, t)

Your'd missed close brackets here:
NV_DS(psi_vec, =, C_U(c0,t0),C_V(c0,t0),C_W(c0,t0) ) ;
NV_DS(psi_vec, +=, C_U(c1,t1),C_V(c1,t1),C_W(c1,t1) ) ;

Once you click Build (compile udf library) look at console panel in Fluent, you will see information about errors

Best regards

[Prabhumsrit]

Sir, compiling error not coming

[Prabhumsrit]

After run simulation only error occuring

[Prabhumsrit]

If I change ZONE ID TO boundry face running

[Prabhumsrit]

Here problem is interior face

[AlexanderZ]

Fluent gave me this output, when I've tried to compile your code:

..\..\src\new_test1.c(20) : error C2065: 'begin_c_loop' : undeclared identifier
..\..\src\new_test1.c(20) : error C2143: syntax error : missing ';' before '{'
..\..\src\new_test1.c(23) : fatal error C1057: unexpected end of file in macro expansion

there are a lot of problems...

why do you use 2 as thread, but in you picture interior has ID=6?

t= Lookup_Thread(d, 2);

As I understand you need only velocity magnitude, so you do not need any vector operations.

So try to find NV_MAG macros, and apply it to your problem,
Best regards

[Prabhumsrit]

Dear Mr. AlexanderZ



#include "udf.h"
#include "mem.h"


DEFINE_EXECUTE_AT_END(Velocity)
{
Domain *d;
face_t f;
cell_t c0, c1 = -1;
Thread *t, *t0, *t1 = NULL;
real NV_VEC(psi_vec), NV_VEC(A), flux = 0.0;
c0 = F_C0(f,t);
t0 = F_C0_THREAD(f,t);
F_AREA(A, f, t);
d = Get_Domain(1);
t= Lookup_Thread(d, 6);
begin_f_loop(f,t)
{
c1 = F_C1(f,t); /* Get cell on other side of face */
t1 = F_C1_THREAD(f,t);
NV_MAG(psi_vec, =, C_U(c0,t0),C_V(c0,t0),C_W(c0,t0));
NV_MAG(psi_vec, +=, C_U(c1,t1),C_V(c1,t1),C_W(c1,t1));

}
end_f_loop (f, t)
}


Whatever u telling is correct. I want magnitude of velocity at interior face(nozzle exit).

Compiling and Error msg is attached

Please send any simple example to calculate the magnitude of velocity at the interior face.

Thanks for fast reply