CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

Pressure boundary condition

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

LinkBack Thread Tools Search this Thread Display Modes
Old   September 16, 1999, 13:21
Default Pressure boundary condition
Luigi Scivoletto
Posts: n/a
I'm working with the incompressible Navier-Stokes equations with a moving boundary (free-surface flows). I solve the 3D hydrodynamic field by Finite Volume Method with a fractional step procedure, where a Poisson equation must be solved in order to ensure the mass conservation. I've a problem about the outlet pressure boundary condition. When pressure and velocity are unknown at the outlet of the domain, in fact, the simmetry boundary condition is commonly employed for the velocity. In this case, what is the correspondent boundary condition for the pressure in the Poisson equation?

Thanks for your time and for your answers.
  Reply With Quote

Old   September 16, 1999, 14:20
Default Re: Pressure boundary condition
Steve Ciesla
Posts: n/a
The NS equations deal with the pressure gradient, so the pressure value itself is not critical. Usually, an arbitrary value is placed at one point in the domain. For example, in a square driven cavity put the pressure equal to zero at the center of the bottom wall. Good Luck!

Steve Ciesla
  Reply With Quote

Old   September 28, 1999, 15:41
Default Re: Pressure boundary condition
Yangang Bao
Posts: n/a
Could you kindly tell me how to derive Poisson's equation for pressure for Non-Newtonian fluid? I am trying to derive a Poisson-like equation using a method similar to SIMPLE-algorithm, but it seems doesn't work for 3D using tetrahedron elements. Thanks.

  Reply With Quote

Old   September 28, 1999, 16:37
Default Re: Pressure boundary condition
Posts: n/a
Take the divergence of the momentum equation to get a Poisson equation. Then introduce the continuity equation into the time derivative terms.
  Reply With Quote


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
Wind turbine simulation Saturn CFX 58 July 3, 2020 01:13
mixed inflow/outflow downstream boundary condition question peob OpenFOAM Running, Solving & CFD 3 February 3, 2017 10:54
Pressure boundary condition C-H Kuo Main CFD Forum 18 September 16, 2016 03:19
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Pressure Boundary condition abishek FLUENT 1 July 28, 2008 08:14

All times are GMT -4. The time now is 17:18.