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

UDS for compressible flow

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

LinkBack Thread Tools Display Modes
Old   February 4, 2012, 19:44
Default UDS for compressible flow
Senior Member
Join Date: Jun 2010
Posts: 111
Rep Power: 9
Hooman is on a distinguished road
Hi, Quick question on Upwind differencing scheme in finite volume, for compressible flows, where density and velocity both vary.
I know that when density and velocity are constants, then you would have:
\left[\frac{\partial(\rho u\phi)}{\partial x}\right]_{i}=\rho u\frac{\phi_{i}-\phi_{i-1}}{x_{i}-x_{i-1}} if \rho u > 0
\left[\frac{\partial(\rho u\phi)}{\partial x}\right]_{i}=\rho u\frac{\phi_{i+1}-\phi_{i}}{x_{i+1}-x_{i}} if \rho u < 0

Can someone please tell me what happens when density and velocity are variables. Would I get something like this?

\left[\frac{\partial(\rho u\phi)}{\partial x}\right]_{i}=\frac{\left(\rho u\phi\right)_{i}-\left(\rho u\phi\right)_{i-1}}{x_{i}-x_{i-1}} if \rho u > 0

\left[\frac{\partial(\rho u\phi)}{\partial x}\right]_{i}=\frac{\left(\rho u\phi\right)_{i+1}-\left(\rho u\phi\right)_{i}}{x_{i+1}-x_{i}} if \rho u < 0

I'm guessing the same principle applies even if density is constant and velocity varies.

I didn't manage to find anything useful online. Please help!


Last edited by Hooman; February 5, 2012 at 05:51.
Hooman is offline   Reply With Quote


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
UDS Flux Function Choice Yang Chung FLUENT 1 November 17, 2015 02:14
Non-steady flow simplified for use in Vissim steamerandy Main CFD Forum 0 October 31, 2011 22:08
Flow meter Design CD adapco Group Marketing Siemens 3 June 21, 2011 08:33
potential flow vs. Euler flow curious ... Main CFD Forum 23 July 21, 2006 07:40
Plug Flow Franck Main CFD Forum 3 September 4, 2003 05:57

All times are GMT -4. The time now is 18:48.