|
[Sponsors] |
March 7, 2012, 11:53 |
Proper boundary conditions
|
#1 |
New Member
Join Date: Mar 2012
Posts: 1
Rep Power: 0 |
Dear CFX users,
I faced a problem in setting boundary conditions of a pure free convection problem. A box has two openings: one is located at higher elevation and another is located lower. Just guess the cavity flow with two openings. My question is, What should be the boundary condition at those openings? I set opening (entrainment) boundary conditions with zero relative pressure and 25C static temperature (ambient). But my adviser said its wrong. He said that I should not set any temperature and pressure at those openings. It might be calculated from the internal flow. Anyway as I know, we set pressure and temperature at the opening as the ambient conditions. If anyone has better experience, please kindly share. Thanks. |
|
March 7, 2012, 18:54 |
|
#2 |
Senior Member
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,167
Rep Power: 23 |
If your adviser knows what is "wrong" he should be able to suggest what is "right".
You cannot just omit the temperature if there is inflow though, it sound to me like your adviser should rethink his statement. Do both of the openings have only inflow or only outflow? |
|
March 7, 2012, 19:39 |
|
#3 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
You define the boundaries at places you know the conditions. If you know the pressure then define that. If you know the velocity/flow rate then define that. You cannot define a boundary at a location you know nothing - you must define either the pressure or velocity. Also you cannot define both pressure and velocity, that is over specifying the boundary.
|
|
October 25, 2013, 01:05 |
|
#4 |
Senior Member
Svetlana Tkachenko
Join Date: Oct 2013
Location: Australia, Sydney
Posts: 407
Rep Power: 14 |
Did you figure it out?
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
mesh file for flow over a circular cylinder | Ardalan | Main CFD Forum | 7 | December 15, 2020 13:06 |
non reflective boundary conditions for incompresible flow | Pascal_doran | OpenFOAM Programming & Development | 16 | August 25, 2015 05:35 |
[Netgen] boundary conditions and mesh exporting | vaina74 | OpenFOAM Meshing & Mesh Conversion | 2 | May 27, 2010 09:38 |
Concentric tube heat exchanger (Air-Water) | Young | CFX | 5 | October 6, 2008 23:17 |
Fluent accuracy and boundary conditions | Paolo Lampitella | FLUENT | 0 | June 12, 2008 06:25 |