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

Pressure boundary conditions

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

LinkBack Thread Tools Search this Thread Display Modes
Old   August 5, 2007, 16:38
Default Pressure boundary conditions
Lionel S.
Posts: n/a
Hi all,

First I thought that if you have a boundary condition which imposes pressure only, the velocity at that point is taken as being the same as the neighbouring cell. In fact it imposes

grad(v)*n = 0

near to the pressure (outflow) boundary, but I supposed that for many flows, it's not a problem.

Now I wonder if solving the unknowns for boundary conditions would make the system a little less stiff.

The problem is: I already have 3 equations (Navier Stokes X and Y and continuity) for each cell, as well as 3 unknowns (X and Y velocities and P). I cannot solve it if I have additional unknowns for boundary conditions. The problem for boundary conditions imposing velocity only is the same.

Some people told me to read Versteeg and Malalasekera, but I didn't find exactly what I search.

Any idea ? Thanx in advance

  Reply With Quote

Old   August 24, 2007, 18:03
Default Re: Pressure boundary conditions
pankaj saha
Posts: n/a
for pressure b.c----

on the outflow---p=0 and any other plane normal gradient of p is =0

try it.
  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
mass flow in is not equal to mass flow out saii CFX 12 March 19, 2018 05:21
Implementation of boundary conditions for FVM Tom Main CFD Forum 7 August 26, 2014 05:58
Pressure Boundary Conditions Dave FLUENT 2 June 8, 2009 17:05
pressure boundary conditions A.Shaija Main CFD Forum 0 June 30, 2006 00:51
How to Define Pressure Boundary Conditions? Sheenu Main CFD Forum 4 May 12, 2000 12:52

All times are GMT -4. The time now is 00:55.