CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Phoenics

Defining cell faces in BFC

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 24, 2003, 04:07
Default Defining cell faces in BFC
  #1
Olof Liungman
Guest
 
Posts: n/a
I have for many years pondered how the cell faces in a non-orthogonal BFC grid are defined. This is important when determining whether a particle is inside a certain cell, where the velocity components are situated and what the face area is.

Consider the following example: an otherwise cubic cell has three nodes on its LOW face at Z = 0.0, but the fourth at Z = -0.1, i.e. a little lower than the other three. These four nodes are then NOT on a plane. So how does PHOENICS define the LOW cell face?

One idea that a colleague came up with is as follows. Calculate the "mean" position of the four nodes in question (call it the center position, P). Then draw four triangles, each with its tip at P and bases along the four segments made up of the sides between the four nodes. We now have four well-defined planes (3D triangles), with well-defined areas and a (kind of...) center position P where the W velocity component may be placed.

Is this how PHOENICS does it?

Olof
  Reply With Quote

Old   July 24, 2003, 09:48
Default Re: Defining cell faces in BFC
  #2
Rami
Guest
 
Posts: n/a
Hi Olof,

I also wondered about the same question - i.e., how nonplanar cell faces are dealt with - some years ago. Since I did not find an answer, I bypassed it altogether by FORCING planar cell faces during the (BFC) grid generation, e.g., by pure rotation of a planar grid. This was sufficient for my purposes, but it may be not general enough for your needs.

I hope this helps somewhat, Rami
  Reply With Quote

Old   July 28, 2003, 04:23
Default Re: Defining cell faces in BFC (Att. CHAM)
  #3
Olof Liungman
Guest
 
Posts: n/a
Well, Rami, I suppose we are both eagerly waiting to hear CHAM's answer. Anyone from CHAM reading this? If so, please enlighten us.

Olof
  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Defining new faces after fluenttofoam conversion mayank OpenFOAM Mesh Utilities 3 June 4, 2007 10:13
Mapping cell faces to other cell faces doug OpenFOAM Meshing Format & General Technical 5 March 30, 2007 02:43
Defining boundary conditions on interior faces melanie OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 9 August 10, 2006 09:52
Defining and assigning a variable to a cell Robi FLUENT 0 July 13, 2005 18:27
Defining a new cell variable Ulrich FLUENT 1 May 25, 2000 16:04


All times are GMT -4. The time now is 20:26.