code_saturne User's Forum

I have a problem with particle tracking. My geometry is actually pretty simple. It is a
My boundaries are set up as followed:
I have a wall, an outlet and an inlet. Thought the thing is, that my inlet is sucking, which means i have a negative volumic flow rate. That is because I only now the exact volumic flow rate at the outlet. When I try to set up the particle tracking it only allows me to define my particle inlet on my flow inlet. So in the calculation it injects 10 particles and immediately eliminates the 10. So I never have a particle in my control volume. I tried to define the outlet as free inlet/outlet but then I cant select the menu for particle boundaries.
Is there a different way to set the problem?
I am using CS4.0
Joscha

Hello,

Do you have multiple inlets or outlets ?

I'll check with the main developer of the GUI to see if this is a GUI bug or a current limitation of the Lagrangien Boundary conditions handling (in which case we'll try to improve things, but the fix won't be immediate).

Is your flow transient or coupled (i.e. feedback) with the Lagrangian part,, or is it possible for you to compute a steady flow solution first, then do the Lagrangian run with a frozen flow field ? In which case you could use a "standard" inlet in the restarted computation, basing it on the restarted computation inlet values (this would require a relatively simple setup of a user subroutine, but I could guide you through this).

Regards,

Yvan

Hey,
thanks for the reply. I was already wondering, if I could define the result of my steady calculation as an inlet condition. I was already looking into the subroutines, but I started working with CS only 2 month ago. Would be great, if you could guide me a little bit.
I have a transient but not a coupled flow. I only have the boundaries showed in the picture: one of each.
The xml file is the SetUp for the steady calculation I already have.
Joscha

Hello,

If you flow is transient, the frozen carier flow approach won't be applicable. I'll have to lok at the Lagrangian user subroutines to see how to solve/workaround your problem, but I won't be able to get the time to do this before a few days. I'll keep you updated as soon as I can.

Regards,

Yvan

ok Thanks,
I will try to get to know better the subroutines.