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UDF to monitor minimum pressure on the wall

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Old   September 20, 2007, 11:53
Default UDF to monitor minimum pressure on the wall
Arvind Jayaprakash
Posts: n/a
Hello World!

Can any of you help me debug the UDF appended below. I am trying to identify the minimum pressure on the wall at the end of each time step. It is a 2D flow over a airfoil problem.


/************************************************** *********************************************** -----USER DEFINED FUNCTION HOOKS Fluent V6.3---------------------

UDF to identify the lowest pressure on the wall at the end of each time step ************************************************** ************************************************/

#include "udf.h" #include "stdio.h" #include "mem.h " #include "threads.h"


real pmin =0.;

real pre;

real flow_time = RP_Get_Real("flow-time");

int ID = 7; /* Enter the zone ID of Wall from the Boundary Conditions Panel*/

/* Get the domain using Fluent utility */

Domain *d;

d = Get_Domain(1);

/* Get the thread ID */

Thread *t = Lookup_Thread(d, ID);

face_t f;

if (BOUNDARY_FACE_THREAD_P(t)) /* Check the for boundary face thread */


FILE *fp = NULL;

char filename[ ]="wall-minimum-pressure.txt";

fp = fopen(filename, "w");

/* Loop over all faces in the wall face-thread */

begin_f_loop(f, t)


pre = F_P(f,t); /* get face pressure */

if (pre < pmin) pmin = pre; /* Compute minimum face pressure */



Message("\nWriting the lowest pressure on the wall to %s...",filename);

fprintf(fp,"%g %f \n",pmin,flow_time);





Error("Please enter the correct Zone ID from the Boundary Conditions Panel");


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