Hi,

For transient calculations of a non reacting system with 2 inlets (one for gas A and one for gas B) and one outlet for a mixture A+B,

I have to report the mass fraction of B as a function of time step for all the cells at the outlet.

Any one know hows to start/writte an UDF to make that possible?

I tried to use your udf that cg suggested to me as an interpreted one but I got the following error message :

cpp -ID:\FLUENT.INC\fluent6.0/src -ID:\FLUENT.INC\fluent6.0/cortex/src -ID:\FLUENT.INC\fluent6.0/client/src -ID:\FLUENT.INC\fluent6.0/multiport/src -I.

-DUDFCONFIG_H="<udfconfig.h>" C:\FLUENT\projects\udf.cError: C:\FLUENT\projects\udf.c: line 11: parse error. Error: C:\FLUENT\projects\THALES\udf.c: line 20: f_loop_last: undeclared variable

I tried also to use it as a compiled one and got the following error message : Opening library "libudf"...

Error: open_udf_library:....

is there a path problem?

Here is the udf :

______________________________________

#include "udf.h"

DEFINE_ON_DEMAND(species_mass_flow) {

Domain *domain = Get_Domain(1);

Thread *t; face_t f;

thread_loop_f(t,domain);

real f

real smf

if( THREAD_TYPE(t)==THREAD_F_POUTLET )

begin_f_loop (f,t)

{

real smf = F_FLUX(f,t)*F_YI(f,t);

}

end_f_loop(f, thread)

Message("%i %e\n",f,smf);

}

end_f_loop (f,t) }

_________________________________________

any one can help ? Thanks.

Hi Laura

There is a couple of syntax errors in UDF. Try compiling this version

#include "udf.h"

DEFINE_ON_DEMAND(species_mass_flow)

{

real smf;

int species_index = 0;

Domain *domain = Get_Domain(1);

Thread *t; face_t f;

thread_loop_f(t,domain)

{

if( THREAD_TYPE(t)==THREAD_F_POUTLET )

{

begin_f_loop (f,t)

{

smf = F_FLUX(f,t)*F_YI(f,t,species_index);

Message("%i %e\n",f,smf);

}

end_f_loop(f, thread)

}

}

}

you might have to change the species index depeding on which you want to report. hope this helps!

Hi Alek !

Thanks for the answer.

I still get the same error when i compile my udf: Opening library "C:\FLUENT\projects\libudf"... Error: open_udf_library: Le fichier spécifié est introuvable (that means : file not found).

If you agree I can send you my case\data file and the udf (but I don't have your email adress? or may be you prefer to contact : rumba5@voila.fr ?).

May be you can check it if you have time.

Many thanks in advance.

Laura.

Error when I compile my udf as interpreted :

cpp -ID:\FLUENT.INC\fluent6.0/src -ID:\FLUENT.INC\fluent6.0/cortex/src -ID:\FLUENT.INC\fluent6.0/client/src -ID:\FLUENT.INC\fluent6.0/multiport/src -I. -DUDFCONFIG_H="<udfconfig.h>" C:\FLUENT\projects\fraction.cError: C:\FLUENT\projects\fraction.c: line 19: structure reference not implemented

any help please?

variables in () of f _loop are not matching.

what do you mean please?

Hello,

you declare the variable smf twice (in lines 7 and 11) and there are some semicolons missing. By the way: can't you do this report with a surface integral ?

Dirk