what's the udf name to check the availability of face value of velocity?
 

Hello friends,
in my udf, i need to loop the face thread on the boundary, and use the face value of velocity F_U(f,t), F_V(f,t).

However, once i used these two macros, error occurred in fluent.
I guess some of the value on the boundary is not available, so i want to use a check at the beginning. Just like to check the availability of density:
if(THREAD_STORAGE(t,SV_DENSITY)!=NULL)
But i could not find the velocity udf similar to SV_DENSITY to check the velocity.
Anybody could help me?

Now i used this udf, no error occurred, but i am not sure whether this is right.
if(THREAD_STORAGE(t,SV_V)!=NULL&&THREAD_STORAGE(t, SV_U)!=NULL)
{
Ur_F=F_V(f,t);
Uz_F=F_U(f,t);
}
else
{
Ur_F=C_V(c0,t0);
Uz_F=C_U(c0,t0);
}