Applying a vacuum and periodic boundary conditions.

[a.y.al-wardi]

I have a domain representing a vacuum chamber. How do I set the pressure in the domain to represent a vacuum?

I have an inlet injecting ozone into the chamber (vacuum) for a couple of minutes, followed by a hold period in which the inlet is stopped for a couple of minutes, then a purge period with an outlet (purging stage). How do I set up periodic boundary conditions to be applied automatically, and can this be translated into a script for submission to a supercomputing cluster? Or does setting up the case automatically ensure that the periodic boundary conditions are run when submitted to a supercomputing cluster?

Thank you for your help. 

[Rob]

Vacuum in CFD isn't generally recommended as there's "nothing" for the solver to work with. Setting a few hundred Pa is generally sufficient. The function you're looking for is "patch".  For the boundary flow, are you wanting to set an inflow and outflow separately? Ie open/close a valve? Flow profiles (profile or expression) works well, but neither are designed for a flow boundary with zero flow: there are ways around that.