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-   -   THREAD-ID in UDF (http://www.cfd-online.com/Forums/fluent-udf/86178-thread-id-udf.html)

truffaldino March 16, 2011 10:19

THREAD-ID in UDF
 
I would be grateful if someone could help me to fix the problem.

I am using THREAD_ID(t) in if statement to set different visosities in different zones. But it does not work in " if (Thread_ID(t)==...) " statement in my UDF. Whe I run fluent with this UDF, it does not distingush between zones.

It is a very simple code, what could be wrong here?:

PHP Code:


#include "udf.h"

#define xtop -1.
#define xbot 0.

#define rho 1.225
#define nu 1.4607E-5

#define C3 357.9

#define idtop 11
#define idbot 10

DEFINE_TURBULENT_VISCOSITY(mu_tct)
{

real mu;
real nut;
real xi;
real r[ND_ND];

C_CENTROID(r,c,t);

    if(
THREAD_ID(t)==idtop)
    {

            if(
r[0]>xtop)
            {

            
nut=C_NUT(c,t);
            
xi=nut/nu;
            
xi=xi*xi*xi;
            
mu=rho*nut*xi/(xi+C3);

            }
            else 
            {

            
mu=0;

            };

    };

    if(
THREAD_ID(t)==idbot)
    {

            if(
r[0]>xbot)
            {
        
            
nut=C_NUT(c,t);
            
xi=nut/nu;
            
xi=xi*xi*xi;
            
mu=rho*nut*xi/(xi+C3);

            }

            else
            {

            
mu=0;

            };

    };

return 
mu;




Amir March 16, 2011 10:37

Hi,
for simple debugging, would you use a Message command to check whether it enters a if statement or not?

truffaldino March 16, 2011 10:57

Quote:

Originally Posted by Amir (Post 299673)
Hi,
for simple debugging, would you use a Message command to check whether it enters a if statement or not?

I have checked it without message: I have just removed "if(THREAD_ID...) statements and everything works fine, as seen from postprocessing, except it chooses one viscousity function for all zones, so it does not enter "if(THREAD_ID...) statements

truffaldino March 16, 2011 11:03

I have checked it without message: I have just removed "if(THREAD_ID...) statements and everything works fine, as seen from postprocessing, except it chooses one viscousity function for all zones, so it does not enter "if(THREAD_ID...) statements

truffaldino March 16, 2011 11:20

And there is another strange thing: when I put "Message" or "Error" statement, interpretor says:

function "CX_Message" not founs (pc=80)

or

function "CX_Primitive_Error" not found (pc=80)

Amir March 16, 2011 11:52

Quote:

Originally Posted by truffaldino (Post 299685)
I have checked it without message: I have just removed "if(THREAD_ID...) statements and everything works fine, as seen from postprocessing, except it chooses one viscousity function for all zones, so it does not enter "if(THREAD_ID...) statements

just a suggestion:
do not introduce idtop & idbot as:
Code:

#define idtop 11
#define idbot 10

try in define macro:
Code:

int idtop=11
int idbot=10

it may help !

truffaldino March 16, 2011 12:13

Quote:

Originally Posted by Amir (Post 299696)
just a suggestion:
do not introduce idtop & idbot as:
Code:

#define idtop 11
#define idbot 10

try in define macro:
Code:

int idtop=11
int idbot=10

it may help !

Thanks Amir,

I have already tried this: it does not help. I am wanderin, could it be an interpretor problem, since it does not recognize commands like "Message" and "Error"

Amir March 16, 2011 13:38

Quote:

Originally Posted by truffaldino (Post 299705)
Thanks Amir,

I have already tried this: it does not help. I am wanderin, could it be an interpretor problem, since it does not recognize commands like "Message" and "Error"

you're right if you have such these problems with other UDFs with the same headers. is it the case?

truffaldino March 16, 2011 15:29

Thanks Amir,

I have tried with other udf Message and Error macros do not work, so there is something wrong with an interpretter indeed.

truffaldino March 16, 2011 18:39

I have solved the problem: it turns out that zone ID numbers must be taken as assigned by gambit (as in mesh file) and not as shown by fluent!

As for "Error" and "Message" makros they do not work, but can be replaced by "printf".

Amir March 17, 2011 09:57

really? I've used ID's that FLUENT shows for my UDFs before and they've worked.
would you please also checked that with other versions of FLUENT?

natantyt April 3, 2012 18:36

Hi

I've got the same problem with my UDF to define different diffusivities for different zones , did you solve this? I appreciate your suggestions. Did you define the zone ID from boundary box or cell zone box?



Quote:

Originally Posted by truffaldino (Post 299667)
I would be grateful if someone could help me to fix the problem.

I am using THREAD_ID(t) in if statement to set different visosities in different zones. But it does not work in " if (Thread_ID(t)==...) " statement in my UDF. Whe I run fluent with this UDF, it does not distingush between zones.

It is a very simple code, what could be wrong here?:

PHP Code:

 
#include "udf.h"
 
#define xtop -1.
#define xbot 0.
 
#define rho 1.225
#define nu 1.4607E-5
 
#define C3 357.9
 
#define idtop 11
#define idbot 10
 
DEFINE_TURBULENT_VISCOSITY(mu_tct)
{
 
real mu;
real nut;
real xi;
real r[ND_ND];
 
C_CENTROID(r,c,t);
 
    if(
THREAD_ID(t)==idtop)
    {
 
            if(
r[0]>xtop)
            {
 
            
nut=C_NUT(c,t);
            
xi=nut/nu;
            
xi=xi*xi*xi;
            
mu=rho*nut*xi/(xi+C3);
 
            }
            else 
            {
 
            
mu=0;
 
            };
 
    };
 
    if(
THREAD_ID(t)==idbot)
    {
 
            if(
r[0]>xbot)
            {
 
            
nut=C_NUT(c,t);
            
xi=nut/nu;
            
xi=xi*xi*xi;
            
mu=rho*nut*xi/(xi+C3);
 
            }
 
            else
            {
 
            
mu=0;
 
            };
 
    };
 
return 
mu;
 




truffaldino April 4, 2012 04:15

Hello Nathan,

Yes I have solved the problem but it was a long time ago: I remember that it turns out that zone ID numbers must be taken as assigned by gambit (as in mesh file) and not as shown by fluent! That is why my procedure was not working. So, in file I have presented above, it was necessary to change values of idtop and idbottom to those given by gambit in mesh file.

Truffaldino

truffaldino April 4, 2012 04:19

Quote:

Originally Posted by Amir (Post 299862)
really? I've used ID's that FLUENT shows for my UDFs before and they've worked.
would you please also checked that with other versions of FLUENT?

Hello Amir,

I was not aware of your messge, sorry for late responce. Unfortunately I have no access to different versions of Fluent, so I cannot check it.

Truffaldino

Kanarya December 3, 2012 08:51

Hi, I have problem to save mass flow rate at outlet
I did following udf but it seems UDMI doesnt work because it is always zero.
is there anyone who can help me?

thanks in advance!
here is my code:
#include "udf.h"
DEFINE_EXECUTE_AT_END(measure_mass_flow)
{
real mass_flow;
Domain *d=Get_Domain(1);
cell_t c;
face_t f;
Thread *mixture_thread = Lookup_Thread(d,4);
Thread **pt = THREAD_SUB_THREADS(mixture_thread);
Thread *tp = pt[0];
Thread *ts = pt[1];

mass_flow=0.;

mp_thread_loop_f(mixture_thread,d,pt)

if( THREAD_ID(mixture_thread) == 4 )

{
begin_f_loop(f,mixture_thread)

{


F_UDMI(f,mixture_thread,0)+= F_FLUX(f,tp);


}
end_f_loop(f,mixture_thread)
}



}

zwbmimi March 5, 2013 14:36

Hi, I also have this problem and fix it by using the ID provided by FLUENT, which can be found in BC panel.

Kanarya March 6, 2013 05:31

hi Zwbmimi,
thanks for the answer!

I did it as well. But now i have problem to use it in parallel.
Can you use it in parallel..?

best regards


Quote:

Originally Posted by zwbmimi (Post 411754)
Hi, I also have this problem and fix it by using the ID provided by FLUENT, which can be found in BC panel.


zwbmimi March 6, 2013 05:39

Yes, my UDF works in parallel.


Quote:

Originally Posted by Kanarya (Post 411883)
hi Zwbmimi,
thanks for the answer!

I did it as well. But now i have problem to use it in parallel.
Can you use it in parallel..?

best regards


Kanarya March 6, 2013 05:45

for what kind of application are you using it?
can you help me to make it parallel?

thanks in advance...
Quote:

Originally Posted by zwbmimi (Post 411887)
Yes, my UDF works in parallel.


zwbmimi March 6, 2013 05:59

Hi, i include the thread id in source terms of my uds. Does your code work well in parallel without the tread id? I'm happy to help.


Quote:

Originally Posted by Kanarya (Post 411888)
for what kind of application are you using it?
can you help me to make it parallel?

thanks in advance...



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