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Mann January 15, 2008 17:25

Constant pressure!
 
Can some body tell me how to fix a constant pressure within each cell of my simulation! Thanks

Mann

Glenn Horrocks January 15, 2008 17:28

Re: Constant pressure!
 
Hi,

You can turn the hydrodynamic solver off, this will fix the velocity and pressure fields. You do this using an expert parameter. Is this what you want?

Glenn Horrocks

Mann January 15, 2008 20:06

Re: Constant pressure!
 
In the paper they have imposed constant pressure gradient on every cell as a driving force, with fully periodic boundary conditions at the inlet and the outlet. So basically i want to get fixed pressure of -1.59 Pa/m within every cell of my domain before i switch to periodic BC.

I will look into expert parameter tomorrow, but i only want to fix my pressure not velocity field! If you can more precisely explain how to do that it will be very helpful!

Mann

Mann January 15, 2008 20:32

Re: Constant pressure!
 
Sorry i need to obtain a fixed pressure of 0.13 Pa within every cell of my domain because my duct in 0.08m long. If anyone can explain how to do that it will be very helpful!

Mann

Glenn Horrocks January 16, 2008 05:51

Re: Constant pressure!
 
Hi,

It cannot be done. The pressure field is coupled to the velocity field so fixing one and allowing one to float is not physically meaningful.

I would use the translational periodic boundaries with a pressure difference. This feature exists in CFX and is more physically meaningful.

Glenn Horrocks

Usman January 16, 2008 08:30

Re: Constant pressure!
 
Ok makes sense! Thank you Glenn

Usman January 16, 2008 08:34

Re: Constant pressure!
 
One more thing if i specify pressure change in Interface domain, do i need to specify initial velocity in domain initialistaion or global intialistaion.

Usman

Glenn Horrocks January 16, 2008 18:09

Re: Constant pressure!
 
Hi,

A sensible initial guess will improve convergence and is always a good idea.

Glenn Horrocks


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