CFD Online Discussion Forums - Is there an equivalent of "NODE_POS_NEED

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- Fluent UDF and Scheme Programming (https://www.cfd-online.com/Forums/fluent-udf/)

- - Is there an equivalent of "NODE_POS_NEED_UPDATE" for face values? (https://www.cfd-online.com/Forums/fluent-udf/157280-there-equivalent-node_pos_need_update-face-values.html)

Is there an equivalent of "NODE_POS_NEED_UPDATE" for face values?

Hi,

I'm trying to use DEFINE_PROFILE in a transient case and the problem I encounter is that my velocity component data file (which has data for *all* time steps, not just a single one) is read every iteration as opposed to time step, so I was wondering if there is an equivalent to NODE_POS_NEED_UPDATE used in DEFINE_GRID_MOTION? Or is there an alternative way?

Code:

#include "udf.h"







DEFINE_PROFILE(v_component, thread, position)

{

face_t f;

real x[ND_ND];

real y;

double v;

real t = CURRENT_TIME;

FILE *v_values;

v_values = fopen("v_intp.txt","r");



begin_f_loop(f, thread)

{

F_CENTROID(x,f,thread);

y = x[1];



fscanf(v_values, "%lf\n", &v);

Message("The v is %lf\n", v);

Message("The x is %f\n", x[0]);

F_PROFILE(f, thread, position)  = v;

}

end_f_loop(f, thread)

}

In other words, I need to read next profile data lines every time step, not iteration...

Quote:

Originally Posted by Leb (Post 556873)

Code:

#include "udf.h"







DEFINE_PROFILE(v_component, thread, position)

{

face_t f;

real x[ND_ND];

real y;

double v;

real t = CURRENT_TIME;

FILE *v_values;

v_values = fopen("v_intp.txt","r");



begin_f_loop(f, thread)

{

F_CENTROID(x,f,thread);

y = x[1];



fscanf(v_values, "%lf\n", &v);

Message("The v is %lf\n", v);

Message("The x is %f\n", x[0]);

F_PROFILE(f, thread, position)  = v;

}

end_f_loop(f, thread)

}

In other words, I need to read next profile data lines every time step, not iteration...

I believe Fluent will run DEFINE_PROFILE every iteration. So,just put your reading/close file function in it. The profile will be updated every iteration.

Thanks for your reply, but as I mentioned, I do *not* want to update the profile every iteration, but every time step.

I was hoping that I could use something like this:

Code:

if (t = 0.000000)

        u_values = fopen("u_comp_0.txt","r");

else

        {

        u_values = fopen(strcat(strcat(foo,str),bar ),"r");

        }

where

Code:

strcat(strcat(foo,str),bar )

is simply the division of CURRENT_TIME by my time_step (which is fixed), but I got a fatal signal (ACCESS_VIOLATION) for some reason...