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

pressure ratio between two parallel walls ??

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 5, 2008, 09:10
Default pressure ratio between two parallel walls ??
  #1
frank
Guest
 
Posts: n/a
Hi,

I just simplify my question as:

I have two paralle node-to-node walls in my flow field. Now, I want to have the pressure ratio between the two walls. That is

P_i(wall1)/P_i(wall2)

Can I have this parameter in cfx solving process?

Thanks for your reply.

frank
  Reply With Quote

Old   July 6, 2008, 22:54
Default Re: pressure ratio between two parallel walls ??
  #2
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Write it to a monitor point with the CEL expression. Then you see it in Solver manager as the simulation progresses.

Glenn Horrocks
  Reply With Quote

Old   July 7, 2008, 22:17
Default Re: pressure ratio between two parallel walls ??
  #3
frank
Guest
 
Posts: n/a
Thanks for your reply,Glenn Horrocks

How to use CEL for two different surfaces,although they have the same number of nodes?

something like this?

P@surface1/P@surface2

This syntax seems unlawful for CEL.

pls give more hints about this.

Thanks
  Reply With Quote

Old   July 7, 2008, 22:25
Default Re: pressure ratio between two parallel walls ??
  #4
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Try something like "areaAve(p)@surface1". The syntax of the CEL language is detailed in the CFX reference manual.

Glenn Horrocks
  Reply With Quote

Old   July 7, 2008, 23:39
Default Re: pressure ratio between two parallel walls ??
  #5
frank
Guest
 
Posts: n/a
To Glenn Horrocks I know this function,this will give out the average ratio of surface1's and surface2's pressure in a whole, not the pressure ratio of the on node to node base. Suppose we have N nodes for each surface, what I want is to get N ratio values.That is to say it is a distribution function.

But thank you all the same.

  Reply With Quote

Old   July 8, 2008, 18:23
Default Re: pressure ratio between two parallel walls ??
  #6
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

What are you trying to do? Exactly what do you want the pressure ratio of?

Glenn Horrocks
  Reply With Quote

Old   July 8, 2008, 22:37
Default Re: pressure ratio between two parallel walls ??
  #7
frank
Guest
 
Posts: n/a
Hi,

I am modeling the phenomena of concentration overpotential in fuel cell porous media which will depend on the pressure ratio of two boundaries.

Similar case happen to the surface electric resistence for two connecting surfaces. There will be a electric potential jump between the two surfaces, which we should use the potential of one surface and the potential jump to express the other surface's electric potential.

So, I find this is a fault of cfx of disability to refer variables at two different places, even at domain interface.
  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
Fluent natural ventilation pressure boundary condition pierresandre FLUENT 24 November 8, 2011 14:32
high pressure ratio keeper CFX 10 August 2, 2010 07:33
UDF to define or adjust pressure??? engahmed FLUENT 0 July 6, 2010 17:19
Neumann pressure BC and velocity field Antech Main CFD Forum 0 April 25, 2006 02:15
Definition of pressure Ola Nordblom FLUENT 1 August 16, 2001 15:58


All times are GMT -4. The time now is 17:47.