[EL OMARI Achraf]

Hi everyone,
I'm getting the following warning when I compiled a UDF function in Fluent. I obtained the following warning:

warning C4700: uninitialized local variable 'x' used

is this program right, or something is missing??


#include "udf.h"
#define PI 3.14
#define A 20.0
#define freq 10.0

DEFINE_PROFILE(unsteady_inlet_x_velocity, thread, position)
{
real y[ND_ND] ;
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_PROFILE(f,thread, position) = sin(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI*(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}

DEFINE_PROFILE(unsteady_inlet_y_velocity, thread, position)
{
real y[ND_ND];
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_PROFILE(f,thread, position) = cos(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}

[LuckyTran]

just follow the error message

Originally Posted by EL OMARI Achraf

real x;

you declared x here

Originally Posted by EL OMARI Achraf

F_PROFILE(f,thread, position) = cos(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI(x-0.001))*sin(freq*2.*PI*t);

You called x here and also later but never assigned any values to x.

Check out the example from the Fluent manual. You are missing lines that should look like so:

F_CENTROID(y, f, thread);

x = y[0];

F_Centroid is a macro that loops over the face thread f and stores the centroids into variable y. Hence why you declare real y[ND_ND]; instead of just real y;
x=y[0] takes the 1st value of the centroid coordinate (the x position in this case). If you want the y coordinate then do y[1], and do y[2] if you want the z coordinate.

[serrar]

Thanks a lot for your advice, I did everything you asked me to do but I still get the error mentioned above
------------------------------------------------------------------------------------
vprofile1.c(31): error C2064: term does not evaluate to a function taking 337 arguments

------------------------------------------------------------------------------------
To clarify things, my basic equation is noted as 1:

1) A*sin(400.*PI*(x-0.001))*sin(400.*PI*(x-0.01))*sin(freq*2.*PI*t)

and concerning the X and Y axes present the projection of this equation according to these axes.

I hoped things were very clear

how can I solve this problem?
Best regards

[serrar]

[AlexanderZ]

put here final version of your code

best regards

[serrar]

Hello everyone,
I hope someone can compile this code and modify or correct it if there are any errors, I would be very grateful.
Best regards
------------------------------------------
#include "udf.h"
#define PI 3.14
#define A 20.0
#define freq 10.0

DEFINE_PROFILE(unsteady_inlet_x_velocity, thread, position)
{
real y[ND_ND] ;
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_PROFILE(f,thread, position) = sin(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI*(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}

DEFINE_PROFILE(unsteady_inlet_y_velocity, thread, position)
{
real y[ND_ND];
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_CENTROID(y,f,thread);
x = y[0];
F_PROFILE(f,thread, position) = cos(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}

[AlexanderZ]

#include "udf.h"
#include "math.h"
#define PI 3.14
#define A 20.0
#define freq 10.0

DEFINE_PROFILE(unsteady_inlet_x_velocity, thread, position) 
{
real y[ND_ND] ;
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_CENTROID(y,f,thread);
x = y[0];
F_PROFILE(f,thread, position) = sin(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI*(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}

best regards

[serrar]

dear AlexanderZ,
thank you very much for your help
to clarify the problem exists only in the part that represents the projection along the axis OY

#include "udf.h"
#include "math.h"
#define PI 3.14
#define A 20.0
#define freq 10.0

DEFINE_PROFILE(unsteady_inlet_x_velocity, thread, position)
{
real y[ND_ND] ; /* projection along the OX axis */
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_PROFILE(f,thread, position) = sin(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI*(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}
----------------------------------------------------------------------------
----------------------------------------------------------------------------
DEFINE_PROFILE(unsteady_inlet_y_velocity, thread, position)
{
real y[ND_ND]; /* projection along the OY axis */
real x;
face_t f;
real t = CURRENT_TIME;

begin_f_loop(f, thread)
{
F_CENTROID(y,f,thread);
x = y[0];
F_PROFILE(f,thread, position) = cos(15.*PI/180)*A*sin(400.*PI*(x-0.001))*sin(400.*PI(x-0.001))*sin(freq*2.*PI*t);
}
end_f_loop(f, thread)
}
----------------------------------------------------------------------
----------------------------------------------------------------------


Best regards

[AlexanderZ]

to clarify - no

best regards