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F_YI(f,t,i) is creating a problem

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Old   May 23, 2009, 06:46
Default F_YI(f,t,i) is creating a problem
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itoa
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Hello everybody,

Here is the UDF

#include "udf.h"

DEFINE_ADJUST(mfrac,domain)
{
FILE *fp;
float mfrac;
int i = 0;
int zone_ID = 2;
Thread *thread = Lookup_Thread(domain,zone_ID);
face_t f ;
fp = fopen("check.txt","w+");
begin_f_loop(f, thread)
{
mfrac = F_YI(f,thread,i); /* Here lies the problem */
fprintf(fp,"%d\n",mfrac);
}
end_f_loop(f, thread)
fclose(fp);
}

The zone_ID is for a wall.
I have compiled this successfully but it gives ACCESS VIOLATION.
But when i replace F_YI with F_T there is just no problem at all.
F_YI(f,thread,i) is causing this error.
But i am unable to figure out the mistake.
Any help is highly appreciated


techy
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Old   May 23, 2009, 07:30
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itoa
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there is a small mistake

fprintf(fp,"%d\n",mfrac);

as mfrac is defined as float
so i am using

fprintf(fp,"%f\n",mfrac);

but F_YI(f,t,i) is still causing that error

Please help somebody

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Old   May 23, 2009, 09:54
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Daniel Tanner
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Not sure what the problem is!
Are you sure F_T is working?
Some quick things to try:
1) Do you need to include "fstream.h"?
2) Should the face_t f; come before the Thread *thread... statement?
3) Remove the file commands (FILE, fp, fprintf, fclose) and see if that helps.
Sorry not sure why it has a problem. Good luck
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Old   May 24, 2009, 03:10
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itoa
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yes Daniel F_T is working for sure.

I have tried everything you listed without
any effect.

Please help somebody its a bit urgent.

Techy
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Old   May 24, 2009, 06:00
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Daniel Tanner
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I saw the following on a different forum:
http://university.fluent.com/forum/v...e6ba41c1408da3

It gives some useful bits of info:
"The macros C_YI, F_YI cannot be used while using pdf combustion model.

The species mass fractions can be accessed using the macro Pdf_Yi(c,t,i). When using this macro, please include the library sg_pdf.h in your UDF."

Sorry, I have no other ideas!
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Old   May 24, 2009, 11:23
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thanks daniel

but i am only using species transport and nothing
else.
means no benefit from Pdf_Yi

But i am sure this forum is
gonna certainly solve my problem.

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Old   September 3, 2009, 08:03
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Byron Smith R J
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Hai,
The problem is that mfrac is not defined as a array whereas F_YI(c,t,i) generates an arrray of mass fractions of species.

Byron SMith
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Old   April 2, 2015, 05:36
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I am using Non-premixed model in Ansys 14.0.
The description in
3.2.3.6.1.*Species Fractions Calculations with the Non- and Partially- Premixed Models
says that "... Pdf_Yi(c, t, n) or Pdf_XY(c,t,x,y). The functions are defined in the header file pdf_props.h, which you will need to include in your UDF."

However, I would like to acquire the species fraction on a certain face.
In other cases without Non-premixed model, it should be F_YI(f,t,i).
Could anyone kindly tell me how to get the mass fraction on a face when using Non-premixed model?
Thank you!
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