udf for Cd calculation
 

Hi, I'm trying to use a compiled udf to change the cd coefficient used by Fluent 5.4, but the procedure written on fluent manual doesn't fit with the one described in makefile file, that, in any case, doesn't work. Someone has any suggestion for me? Thanks and best regards Micaela

udf information
 

Hi!I'm a Fluent 5 user and i would to known how can to write on a file the value for a variable declaired into the UDF subroutine. Thanks and best regards. Gino

Re: udf information
 

try below program , it's correctly, DEFINE_ADJUST(adj_func,domain) is calculated math equation , after the answer deliver transfer into DEFINE_SOURCE(name,c,t,ds,eqn).so DEFINE_ADJUST is subroutine , DEFINE_SOURCE(name,c,t,ds,eqn)is main program . best regards for you

#include "udf.h"

Thread *t; cell_t c;

real Yo2; real Pc; real Xo2;

DEFINE_ADJUST(adj_func, domain) { thread_loop_c(t, domain) { if( THREAD_ID(t) == 4 ) /* "4" shows your fourth floor ID */ {

begin_c_loop(c, t)

{

Yo2 = C_YI(c, t, 0); /* gets cell mass fraction */

Pc = C_P(c, t); /* gets cell pressure */

Xo2 = Yo2*Pc;

C_UDMI(c,t,0) = Pc*Xo2;

}end_c_loop(c, t) } } }

DEFINE_SOURCE(ff,c ,t, dS, eqn) { real source; source = C_UDMI(c,t,0)*12.; dS[eqn] = 12.;

return source; }