[sufjanst]

Hello everyone,

I am pretty new into UDF programming. I try to implement a model which is working with the cell wall distance. I can see the wall distance with a contour, but I can not use it in a UDF.

This is my example on how to save the wall distance as a user defined memory. I tried C_WALL_DISt and C_STORAGE_R which are both in the "mem.h"-file.

Here is my code:


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

DEFINE_ON_DEMAND(walldist)
{
Domain *d;
Thread *t;
cell_t c;
d = Get_Domain(1);
face_t f;


thread_loop_c(t,d)
{
begin_c_loop(c,t)
{
//C_UDMI(c,t,1) = C_STORAGE_R(c,t,SV_WALL_DIST);
//C_UDMI(c,t,2) = C_WALL_DIST(c,t);
}
end_c_loop(c,t)
}
}

Compilation works. But whenever I try to execute the function I get a Segmentation Error. Can someone tell me what the problem is?

[AlexanderZ]

the code you've shared does nothing, so it cant generate any problems.
show the code you are using next time

code you need:

#include "udf.h"

DEFINE_ON_DEMAND(walldist)
{
Domain *d;
Thread *t;
cell_t c;
d = Get_Domain(1);

thread_loop_c(t,d)
{
begin_c_loop(c,t)
{
C_UDMI(c,t,0) = C_WALL_DIST(c,t);
}
end_c_loop(c,t)
}
}

don't forget to allocate 1 udmi memory in Fluent GUI
-> user defined -> memory

[sufjanst]

Of course I tried my code without comments, first with C_STORAGE_R and afterwards with C_WALL_DIST...
The code you shared, which is my code without comments, does not work.
User defined memory is allocated

[AlexanderZ]

I have no experience in using C_WALL_DIST(c,t) macro

you may try following:
make a loop in fluid zone only,
turn on any turbulence model, make few iterations
after that run on_demand function