CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Constant pressure!

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 15, 2008, 17:25
Default Constant pressure!
  #1
Mann
Guest
 
Posts: n/a
Can some body tell me how to fix a constant pressure within each cell of my simulation! Thanks

Mann
  Reply With Quote

Old   January 15, 2008, 17:28
Default Re: Constant pressure!
  #2
Glenn Horrocks
Guest
 
Posts: n/a
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
  Reply With Quote

Old   January 15, 2008, 20:06
Default Re: Constant pressure!
  #3
Mann
Guest
 
Posts: n/a
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
  Reply With Quote

Old   January 15, 2008, 20:32
Default Re: Constant pressure!
  #4
Mann
Guest
 
Posts: n/a
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
  Reply With Quote

Old   January 16, 2008, 05:51
Default Re: Constant pressure!
  #5
Glenn Horrocks
Guest
 
Posts: n/a
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
  Reply With Quote

Old   January 16, 2008, 08:30
Default Re: Constant pressure!
  #6
Usman
Guest
 
Posts: n/a
Ok makes sense! Thank you Glenn
  Reply With Quote

Old   January 16, 2008, 08:34
Default Re: Constant pressure!
  #7
Usman
Guest
 
Posts: n/a
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
  Reply With Quote

Old   January 16, 2008, 18:09
Default Re: Constant pressure!
  #8
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

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

Glenn Horrocks
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate Cp (Heat Capacity at Constant Pressure) ? Gian Maria OpenFOAM Programming & Development 5 November 10, 2021 12:53
"Pressure Inlet" Boundary Setup Wijaya FLUENT 15 May 18, 2016 11:08
Abt 'a constant pressure boundary condition' jinwon park Main CFD Forum 3 April 7, 2008 20:36
Does star cd takes reference pressure? monica Siemens 1 April 19, 2007 12:26
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 06:13


All times are GMT -4. The time now is 00:52.