CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

bubble rising problem

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 9, 2010, 08:55
Default bubble rising problem
  #1
New Member
 
srikanth
Join Date: Nov 2009
Posts: 22
Rep Power: 16
swamysrikanth is on a distinguished road
hello frnds,
can anyone explain the way to mesh for bubble rising in a column. i want to study the dynamics of the bubble and deformation of bubble with time. i am confused with the part of creation of bubble...whether i have to create a bubble geometry or i can initialize the bubble injection through boundary conditions. how to do the meshing at critical path of bubble rising through the column...
thanks in advance
srikanth
swamysrikanth is offline   Reply With Quote

Old   September 21, 2010, 17:38
Default Fluid Structure Interaction (even if the structure is just bubble surface tension)
  #2
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,663
Blog Entries: 1
Rep Power: 47
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
There are phase change models that will predict bubbling along the walls (such as in a nuclear reactor).

But it sounds to me that you want to do a bubble of a known diameter rising thru a column...

Do you need to have motion relative to the column (are the ends of the column important) or can we just pretend the bubble is kept still by flow moving the other way? (much simpler to model)

Does the bubble stay in the middle of the column? I hope so.

If you wanted to try that, then you would be talking a nice Hexa mesh with an ogrid around and thru he bubble. It can be meshed in a few minutes, half an hour if you want to get picky about the edge distributions.

If you have deformation, you would have an FSI situation where the flow creates pressures which cause the bubble to deform, which changes the flow and resulting pressures, etc...

I recommend trying a simpler study first (a rigid sphere transient flow analysis), then move towards setting up an FSI solution.

I think you will find this to be quite challenging (mixture of transient and FSI). Have you found any whitepapers on this?

You may also ask this question on the Fluent solver boards in case there is some simpler way to model this two phase problem (not using FSI).
PSYMN is offline   Reply With Quote

Old   September 22, 2010, 09:00
Default
  #3
New Member
 
srikanth
Join Date: Nov 2009
Posts: 22
Rep Power: 16
swamysrikanth is on a distinguished road
thanks for ur reply,
i constructed a hexa mesh on overall column. my case is bubble is moving and it is located in the centre of the column. and it is also deforming with time. and i am running the simulation using vof model.
swamysrikanth is offline   Reply With Quote

Old   May 31, 2016, 12:09
Default
  #4
New Member
 
yesenia
Join Date: May 2015
Location: sydney
Posts: 4
Rep Power: 10
yesenia is on a distinguished road
Hi srikanth!

I'm also trying to simulate a bubble motion in fluent using VOF. I just want to know how big was your geometry and how do you mesh it.
I have a geometry of 18x18x18 mm and the bubble is 2mm. But I want to have a refine mesh in the bubble and interface. I would like to have cell with 2.5 microns in the interface but I'm not sure what is the best way to do without having a huge amount of elements.

Thanks
yesenia is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[Commercial meshers] Handling cyclic BC from gambit to openfoam for a cascade airfoil problem - OF 1.6 maverick OpenFOAM Meshing & Mesh Conversion 2 June 18, 2011 05:36
Velocity profiles problem behind the elbow (3D problem) kabat73 FLUENT 8 May 9, 2010 05:26
Single Bubble Gerrit Senger CFX 4 March 12, 2007 17:29
Vapour bubble integrity Matjaz Kariz CFX 0 November 18, 2004 16:30
Can CFD help solve air bubble problem? Tim Luxon Main CFD Forum 2 November 16, 2000 12:02


All times are GMT -4. The time now is 06:45.