Hi. Now I wannt get the sum pressures on two walls then use the sum as a pressure boundary condition applied on one inlet. My problem is how to get the wall ID and how to get pressures. Thank you very much.

You can get the zone id of wall through boundary condiitons panel; then use Lookup_Thread to get the thread for the wall and get the pressure using F_P(c,t)

thank you for your hint. I can't set the domain value in the Lookup_Thread function. ...

You have to get the domain through Domain *d= Get_Domain(domain_id), where domain_id will be 1 for single phase problems and multiphase problem 1 for mixture domain and for each phase you can get the domain id from the phases panel.

Hi,

I am Ravi doing chemical engineering B.Tech. at IIT Kharagpur.

In my case, there is simultaneous Mass Transfer and fluid trasfer. I want to give velocity profile at a boundary but the concentration of a species also depends on that velocity by a function. so,i have written a udf which works for both velocity and mass fraction at that boundary, can you please tell me how should i call velocity variable and mass fraction variable in the define_profile macro... since mass fraction is a scaler so how can i give it within the face thread, is F_V(f,t)for velocity and F_YI(f,t,i) for concentration correct or do i need to define cell thread for mass fraction.

Kindly reply as soon as possible as my work is stuck up because of this only. If possible please mail me at ravii.iitkgp@gmail.com.

Thanks.

for velocities F_U(f,t), F_V(f,t), F_W(c,t) can be used, But for some boundaries these values not stored(eg symmetry), there u may have to use the nearby cell value

F_YI(f,t,i) is correct for species mass fraction, it will work on face too.