How to get UDS on interior face?
 

Hi guys,

I want to get the UDS on a interior face. As the 'UDF manual' says, no value of UDS is stored on face. So I tried to find the value on adjacent cell. Here comes the questions:

1. First thing I should do is find the face thread of interior. Knowing the ID of interior, which domain should I look up into for the interior, when the interior is a interface between two different fluid zones? Will that make any difference?

2. After I find the interior face thread from one zone, are the values of adjacent cell on both sides available for me?

Here is the UDF which I used. But I did not get any value return.:confused:

/*Description:3 fluid zones (ID 17,19 and 18 from left to right);*/
/* 2 interior faces between 3 zones (ID 29,30 from left to right)*/

DEFINE_DIFFUSIVITY(myuds_diffusivity,c,t,i)
{
Thread *sr,*rl,*src,*rlc;
int a;
real dif;
cell_t c0;
face_t f;
real tall,tavesr,taverl;
Domain *domain0,*domain1;
domain0=Get_Domain(17);
domain1=Get_Domain(18);
sr=Lookup_Thread(domain0,29); /*LOOKUP THREAD 29 IN ZOON 17*/
rl=Lookup_Thread(domain1,30); /*LOOKUP THREAD 30 IN ZONE 18*/
src=THREAD_T0(sr); /*FIND THE CELL THREAD*/
rlc=THREAD_T0(rl); /*FIND THE CELL THREAD*/
a=0;
tall=0.0;
begin_c_loop(c0,src) /*LOOP IN CELL THREAD*/
{
a=a+1;
tall=tall+C_UDSI(c0,src,0);
C_UDMI(c0,src,2)=C_UDSI(c0,src,0);
}
end_c_loop(c0,src)
tavesr=tall/a;
tall=0.0;
a=0;
begin_c_loop(c0,rlc) /*LOOP IN CELL THREAD*/
{
a=a+1;
tall=tall+C_UDSI(c0,rlc,0);
C_UDMI(c0,rlc,3)=C_UDSI(c0,rlc,0);
}
end_c_loop(c0,rlc)
taverl=tall/a;
dif=5.67*(pow(taverl/100,4)-pow(tavesr/100,4))*emissivity*sample_length/1000/(taverl-tavesr);
}