CFD Online Discussion Forums - UDF for data export?

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UDF for data export?

I want to export heat flux from a panel in a flat plate flow where the temperature of the plate varies with time.

The ASCII automatic data export tool in Fluent is nice, but it creates a new file for every timestep.

Is there a way to write a UDF to export the data from every timestep into a single file in this manner?:

time1|temperature1|vector1 of heat flux from cell center
time2|temperature2|vector2 of heat flux from cell center
...
time100|temperature100|vector100 of heat flux from cell center

If there is could I be pointed to a similar example?

Hi,

Try this udf, it works in serial, you will have to modify the code if you work in parallel:

Code:

#include "udf.h"

DEFINE_EXECUTE_AT_END(execute_at_end)

{

FILE *data;

real coord[ND_ND];

real temperature;

real time = CURRENT_TIME;

real timestep = N_TIME;

Domain *d;

Thread *t;

cell_t c;

d = Get_Domain(1);



if (timestep == 1)

     {

     data = fopen("data.txt", "w");

     fprintf(data, "time x y z temperature\n");

     }

else

     data = fopen("data.txt", "a");



//fprintf(data, "current time is %g s\n", time);



thread_loop_c(t,d)

     {

     begin_c_loop(c,t)

          {

          C_CENTROID(coord,c,t);

          temperature = C_T(c,t);

          fprintf(data, "%g %g %g %g %f\n", time, coord[0], coord[1], coord[2], temperature);

          }

     end_c_loop(c,t)

     }

fclose(data);

}

Thank you I will try it very soon! Right now I've been using Matlab to automate the process of pulling data from each timestep file, but this is a much more elegant solution.