# how to get a upwind node

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 March 24, 2011, 04:11 how to get a upwind node #1 New Member   zhiwei liu Join Date: Mar 2009 Posts: 22 Rep Power: 8 hi, recently, i want to program a project using the high resolution scheme , which is used in CFX. some work has been done but i have no idea about how to get the upwind node to calculate phi_up,especially in hexahedron mesh. maybe i will check the openFoam source code . anyone have some suggestion ?

 May 4, 2011, 23:43 Again,how to find upwind node in FEM? #2 New Member   zhiwei liu Join Date: Mar 2009 Posts: 22 Rep Power: 8 CFX uses CVFEM( control volume FEM)method, and this method is more closer to FEM, i think the common method for finding an upwind node in fem is eough. could anyone give me some clue about finding an upwind node in FEM or CVFEM method? is it a pure mathematic problem?

 May 5, 2011, 04:51 #3 New Member   zhiwei liu Join Date: Mar 2009 Posts: 22 Rep Power: 8 i am sorry. after read more paper,now i think cvfem use the same methods for finding upwind nodes as used in fvm. so i need to read openfoam code carefully to find the strategy used for 3D upwind node finding.

May 6, 2011, 14:04
upwind value
#4
Senior Member

CFDtoy
Join Date: Mar 2009
Location: United States
Posts: 145
Blog Entries: 2
Rep Power: 8
Hi there,
are you coding on your own? if so, did you create a list of face and cell connectivity..then do the following

face loop - on a given face..check flux from cell1 to cell2..if its positive cell1 is upwind cell - else cell2 is the downwind cell and take the properties from cell2.

Evne if you are not coding on your own (i mean basic solver structure is something like openFoams or others), accessing face / cell structure should be straightforward.

My 2c !

Thanks,

CFDtoy

Quote:
 Originally Posted by lzw2003 i am sorry. after read more paper,now i think cvfem use the same methods for finding upwind nodes as used in fvm. so i need to read openfoam code carefully to find the strategy used for 3D upwind node finding.
__________________
CFDtoy

 May 8, 2011, 22:08 #5 New Member   zhiwei liu Join Date: Mar 2009 Posts: 22 Rep Power: 8 Hi CFDtoy, i create my list of face and cell connectivity. if the direction of velocity on face is not parellel to the face normal or there is a big angle between them, ie. the face normal between cell1 and cell2 is parellel to x direction , the velocity is nearly vertical to x directoin and it is positive. shall we also choose the cell1's centre as the upwind node? how does it handle in 3D mesh, is it the same? thanks!

 May 10, 2011, 02:17 #6 Member   lalupp Join Date: Jul 2010 Location: India Posts: 37 Rep Power: 7 In 3d case For each hex cell which has got 6 faces ,there are 6 upstream cells possible. In most of the the codes collocated schemes are used in which pressure and velocity are evaluated at the cell center and face velocity always normal to the common face which has two option either inward or outward (-ve or +ve) Thus to find upstream cell find face velocity (uf) if uf > 0 upstream cell is the parent cell otherwise neighbor cell Try openfvm documentation clearly described

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post kjetil OpenFOAM Running, Solving & CFD 1 November 10, 2012 05:55 subash OpenFOAM 0 May 29, 2010 01:23 Charles FLUENT 0 October 30, 2007 18:48 Ali Doustdar FLUENT 2 July 12, 2007 23:48 Magesh Main CFD Forum 2 July 17, 2003 11:35

All times are GMT -4. The time now is 00:04.

 Contact Us - CFD Online - Top