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

gas velocity looks weird in vicinity of inlet

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 21, 2011, 05:33
Default gas velocity looks weird in vicinity of inlet
  #1
Member
 
Kai
Join Date: May 2010
Location: Shanghai
Posts: 61
Blog Entries: 1
Rep Power: 15
kaifu is on a distinguished road
Hi Foamers,

The gas velocity looks weird when i am doing simulations with solver twoPhaseEulerFoam. The inlet velocity of gas =1.2213 m/s and liquid=0.9214 m/s. However the gas velocity in in vicinity of inlet is always smaller than the one of liquid (gas velocity is larger than liquid velocity elsewhere, see figures). But if I look deep into the problem, I could see a large drag force to push gas bubbles but it failed to speed them up in those cells... I have to mention that here the drag force (on purpose of debug.) is calculated by the velocities (Ua and Ub) not as it is in the solver (where the drag force is calculated by the flux phia and phib).

I have uploaded the case. BTW I am not quite sure about the setup of my pressure boundary conditions at inlet and at walls. I am still confused with BCs between zerogradient and buoyantpressure. Thanks

// Kai
Attached Images
File Type: jpg Ua.jpg (32.0 KB, 6 views)
File Type: jpg Ub.jpg (34.0 KB, 5 views)
File Type: jpg Ur.jpg (33.5 KB, 5 views)
Attached Files
File Type: zip mycase.zip (15.8 KB, 1 views)

Last edited by kaifu; June 21, 2011 at 10:11.
kaifu is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
UDF inlet velocity profile mismatch with Fluent ChristineL Fluent UDF and Scheme Programming 15 November 25, 2016 06:45
Problem with assigned inlet velocity profile as a boundary condition Ozgur_ FLUENT 5 August 25, 2015 04:58
VOF Volume fraction in Velocity inlet aruelle FLUENT 1 March 18, 2010 11:53
Gas velocity Newbie Main CFD Forum 1 April 7, 2003 05:55
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 22:02


All times are GMT -4. The time now is 08:19.