[jbo214]

I want to store some variables using F_UDMI so I can access them later, however I'm having issues with having Fluent store any data.

This is my test UDF:

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


DEFINE_EXECUTE_AT_END(pos_write)
{	
	real pos[ND_ND];
	int zone_ID;

	face_t f; 
	cell_t c;

	Domain *d;
	Thread *t;
	
	zone_ID = 7;

	d = Get_Domain(1);
	t = Lookup_Thread(d,zone_ID);	// choose BC zone ID from BC panel in Fluent
	
	begin_f_loop(f,t)
		{
			F_CENTROID(pos,f,t);
			Message("X = , %f\n",pos[0]);
			F_UDMI(f,t,0) = pos[0];

		}
	end_f_loop(f,t)
}

The UDF prints out the accurate values for the x value of the face centroid in the console, but when I plot the data in the User Defined Memory, everything is just 0. I've double checked that I initialized enough UDM and that I am storing it to the correct index. I also verified that I am using the correct zone ID from the BC panel. I'm using this for a wall BC so F_UDMI is applicable here.

Any ideas?

[`e`]

Fluent is a cell centred solver, and its postprocessing takes values from the cells (either directly, or linearly interpolating for node values). You'll need to apply the same value to the adjacent cell as well to visualise in Fluent with contour plots etc. The adjacent cell and cell thread is retrieved with:

c = F_C0(f,t);
ct = F_C0_THREAD(f,t);

[jbo214]

Originally Posted by `e`

... to visualise in Fluent with contour plots etc. ...

What about just a regular X-Y plot? I followed the steps in the manual and it doesn't seem to assign any values to adjacent cells. They just assign a value using F_UDMI.

/* Compute face temperature and store in user-defined memory */
begin_f_loop(f,t)
     {
          temp = F_T(f,t);
          F_UDMI(f,t,0) = (temp - tmin) / (tmax-tmin);
     }
end_f_loop(f,t)

[jbo214]

I changed my UDF to use the adjacent cell and cell thread. It seems to store the proper information now.

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

DEFINE_EXECUTE_AT_END(pos_write)
{	
	real pos[ND_ND];
	int zone_ID;

	face_t f; 
	cell_t c;
	

	Domain *d;
	Thread *t;

	Thread *ct;
	
	zone_ID = 7;

	d = Get_Domain(1);
	t = Lookup_Thread(d,zone_ID);	// choose BC zone ID from BC panel in Fluent
	
	c = F_C0(f,t);
	ct = F_C0_THREAD(f,t);


	begin_c_loop(c,ct)
		{
			C_CENTROID(pos,c,ct);
			Message("x =  %f\n",pos[0]);

			C_UDMI(c,ct,0) = pos[0];
		}
	end_c_loop(c,ct)			
}