[ham551]

I am trying to apply a wall heat-flux calculated in one simulation, onto a wall in a new simulation. The data is too complicated to fit an expression to, so I decided to try to use a UDF to apply the data extracted from fluent. So I created two array's one holding the x-position, the other the heat flux at that point. Then just used a simple interpolation function.

The UDF compiles, however, when I run the simulation the heat flux is 0 on the wall.

Are there any obvious errors I've made?

#include <udf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
DEFINE_PROFILE(heat_flux,thread,i)
{
real x[ND_ND];
face_t f;
real datasize = 662;
real pos[662] = {
0.0946808 ,
0.0947025 ,
0.094724 ,
0.0947465 ,
0.0947696 ,
...

};

real flux[662] = {
-21979800 ,
-28369700 ,
-10914000 ,
-6822270 ,
-5042960, 

...

};

begin_f_loop(f,thread)
{
F_CENTROID (x,f,thread);
for(int j = 0; j< datasize ; j++)
{
    if(x[0] == pos[j]){
        F_PROFILE(f,thread,i) = flux[j];
    }
    if(x[0]>pos[j] && x[0]<pos[j+1]){
        F_PROFILE(f,thread,i) = flux[j] + ((pos[j]-pos[j+1])*((flux[j+1]-flux[j])/(pos[j+1]-pos[j])));
    }
    else{
        F_PROFILE(f,thread,i) = 0;
    }  
}
end_f_loop(f,thread);
}
}

[AlexanderZ]

next time compile code to get the error log

#include <udf.h>

DEFINE_PROFILE(heat_flux,thread,i)
{
real x[ND_ND];
face_t f;
int j,datasize = 5;
real pos[5] = {
0.0946808 ,
0.0947025 ,
0.094724 ,
0.0947465 ,
0.0947696 
};

real flux[5] = {
-21979800 ,
-28369700 ,
-10914000 ,
-6822270 ,
-5042960
};

begin_f_loop(f,thread)
{
F_CENTROID (x,f,thread);
for(j = 0; j< datasize ; j++)
{
    if(x[0] == pos[j]){
        F_PROFILE(f,thread,i) = flux[j];
    }
    if(x[0]>pos[j] && x[0]<pos[j+1]){
        F_PROFILE(f,thread,i) = flux[j] + ((pos[j]-pos[j+1])*((flux[j+1]-flux[j])/(pos[j+1]-pos[j])));
    }
    else{
        F_PROFILE(f,thread,i) = 0;
    }  
}
end_f_loop(f,thread);
}
}

[ham551]

Originally Posted by AlexanderZ

next time compile code to get the error log

#include <udf.h>

DEFINE_PROFILE(heat_flux,thread,i)
{
real x[ND_ND];
face_t f;
int j,datasize = 5;
real pos[5] = {
0.0946808 ,
0.0947025 ,
0.094724 ,
0.0947465 ,
0.0947696 
};

real flux[5] = {
-21979800 ,
-28369700 ,
-10914000 ,
-6822270 ,
-5042960
};

begin_f_loop(f,thread)
{
F_CENTROID (x,f,thread);
for(j = 0; j< datasize ; j++)
{
    if(x[0] == pos[j]){
        F_PROFILE(f,thread,i) = flux[j];
    }
    if(x[0]>pos[j] && x[0]<pos[j+1]){
        F_PROFILE(f,thread,i) = flux[j] + ((pos[j]-pos[j+1])*((flux[j+1]-flux[j])/(pos[j+1]-pos[j])));
    }
    else{
        F_PROFILE(f,thread,i) = 0;
    }  
}
end_f_loop(f,thread);
}
}

I don't understand what changes you made? The arrays are of length 662, I just shortened it for the purpose of posting here...

[AlexanderZ]

when I compiled your code log file showed me few errors.

of course array should be 662 length in your case