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

Application of a pressure gradient/forcing term in a compressible pipe flow

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 2, 2013, 08:30
Default Application of a pressure gradient/forcing term in a compressible pipe flow
  #1
New Member
 
Michael Sanderson
Join Date: Sep 2011
Posts: 4
Rep Power: 5
mrs206 is on a distinguished road
Dear All,

Im a little bit stuck as to the best way to go about adding a forcing term to a low Mach number compressible pipe flow case. So far, i have played around with the channelFoam method of ensuring a bulk mean velocity, which has worked very well for all of the incompressible cases i have run on the same geometry. Ive also tried specifying a pressure gradient using the fvOptions source term in rhoPimpleFoam which has pretty much the same effect as the channelFoam method, the only difference being that the forcing is applied more times during each time step.

As far as i can tell, the problem with the compressible cases is related to the varying density at the inlet. This causes a change in the velocity at the inlet and also seems to cause a divergence of the pressure gradient to gradually to infinite negative values. I have thought that it may be possible to validate the mass flow rate for this case using a target mass flow value, but im unsure of how to add a source term to phi over the whole internal field. Does this even seem feasible?

Details of my case setup are as follows: 100mm diameter circular tube of 2m in length. Clean pipe with no obstructions. Solved using rhoPimpleFoam with a k-eps model. Mach number of 0.072 with velocity and temperature fixed at the inlet and fixed pressure at outlet. Any comments on the boundary conditions used are welcomed.

Id be very grateful for any help, ive been thinking about this for days without any luck!

Michael
mrs206 is offline   Reply With Quote

Reply

Tags
compressible solver, openfoam, pipe flow, subsonic

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
Unsteady pressure differential between inlet and outlet of the pipe for single phase joshi20h FLUENT 0 September 26, 2012 12:41
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 22:02
pressure gradient term in low speed flow Atit Koonsrisuk Main CFD Forum 2 January 10, 2002 11:52
what the result is negatif pressure at inlet chong chee nan FLUENT 0 December 29, 2001 06:13
Hydrostatic pressure in 2-phase flow modeling (CFX4.2) HB &DS CFX 0 January 9, 2000 14:19


All times are GMT -4. The time now is 16:37.