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

HIgh pressure zone near the outlet?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 24, 2013, 04:43
Default HIgh pressure zone near the outlet?
  #1
New Member
 
wuyu
Join Date: Mar 2010
Posts: 20
Rep Power: 7
seasoul is on a distinguished road
To finetune the settings for my case (which is a valve) using rhoSimplecFoam, I firstly made a simple tube simulation with similar domain dimensions.

It is a pressure driven flow, the pressures at the inlet and outlet are fixed but the velocities are unkown. Thus I set the inlet pressure and outlet pressure with fixed values.

left side, inlet, high pressure.
right side, outlet, low pressure.

For the inlet U it is a pressureInletVelocity bc, but no matter how I changed the outlet bc, for example, pressureInletOutletVelocity, inletOutlet or zeroGradient, after the pressure gradients builds up, there is a large jump near the outlet, which could be seen in the attached figures.

I guess it is a boundary condition setting problem. But I think the options I tried are the most feasible ones, no other options I could think of.

Any suggestions?

Attached Images
File Type: jpg pressure.0050.jpg (16.8 KB, 41 views)
seasoul is offline   Reply With Quote

Old   May 27, 2013, 02:34
Default
  #2
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
hi
What occurs in jump area if you decrease the outlet pressure?
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King.
To Be or Not To Be,Thats the Question!
The Only Stupid Question Is the One that Goes Unasked.
immortality is offline   Reply With Quote

Old   May 29, 2013, 22:01
Default
  #3
New Member
 
wuyu
Join Date: Mar 2010
Posts: 20
Rep Power: 7
seasoul is on a distinguished road
Quote:
Originally Posted by immortality View Post
hi
What occurs in jump area if you decrease the outlet pressure?
Immortality,

The outlet pressure should be fixed at this value based on the application requirement. But I will make one case with decreased pressure to spot the problem.
seasoul is offline   Reply With Quote

Old   June 1, 2013, 05:03
Default
  #4
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
i have a problem like you.
Please let me know how you solved the problem.
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King.
To Be or Not To Be,Thats the Question!
The Only Stupid Question Is the One that Goes Unasked.
immortality is offline   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
Pressure Inlet VS velocity Inlet difference Mohsin FLUENT 6 January 15, 2015 18:15
simple model, difficult outlet Eric CFX 7 May 23, 2014 08:13
replacing of shock tube high pressure part with a boundary condition for low pressure immortality Main CFD Forum 0 May 2, 2013 13:30
Pulsatile pressure inlet with pressure outlet a.lynchy FLUENT 3 March 23, 2012 14:45
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12


All times are GMT -4. The time now is 05:10.