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

FSI and flutter

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 19, 2009, 16:39
Default FSI and flutter
  #1
pop
New Member
 
Ali Pahlavanloo
Join Date: Nov 2009
Posts: 3
Rep Power: 7
pop is on a distinguished road
Hi all!

Does anybody know if it's possible to model flutter in the new ansys 12. I have access to both cfx and FEM solvers.
I have my wing and I want to examine if there is any risk for flutter in subsonic, transonic (thypical transonic dip) and supersonic regions.

Regards
POP
pop is offline   Reply With Quote

Old   November 19, 2009, 17:37
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,651
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Yes, it is possible.
ghorrocks is offline   Reply With Quote

Old   November 20, 2009, 06:13
Default
  #3
pop
New Member
 
Ali Pahlavanloo
Join Date: Nov 2009
Posts: 3
Rep Power: 7
pop is on a distinguished road
Well, Thanks for you short, but honest reply
Could you please give me brief info on where I can find documentations for such simulations?
pop is offline   Reply With Quote

Old   November 20, 2009, 06:29
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,651
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
There are example on general FSI in the CFX examples. For information on how to do this sort of FSI I would look in the open literature, there should be plenty of studies on wing flutter. It is not my field so I cannot help you directly.
ghorrocks is offline   Reply With Quote

Old   January 14, 2010, 20:54
Default Flutter visualization in Ansys CFX
  #5
New Member
 
Berend
Join Date: Jan 2010
Posts: 2
Rep Power: 0
Berend is on a distinguished road
There is indeed a Tutorial on Fluid Structure Interations, tutorial: Oscillating plate. This deals with a forced vibration of a plate in a 2D plane. However, I think flutter can be quite a bit more difficult to obtain. I am dealing with the same challenge.

I would like to visualize potential flutter phenomena occuring with free hanging slender pipes with pump up fluid. At a certain fluid velocity I expect a certain instability of the pipe. This probably require a small initial deflection, but then the fluid will do the work.

Is there somebody who has experience with flutter type of phenomena in Ansys CFX and knows the best way to deal with it.

One of the questions I have have is which turbulence model to use.

Thanks in advance.
Berend is offline   Reply With Quote

Old   January 14, 2010, 21:20
Default Riser stability analysis in Ansys CFX
  #6
New Member
 
Berend
Join Date: Jan 2010
Posts: 2
Rep Power: 0
Berend is on a distinguished road
The problem I am trying to understand is related to earlier observed unstable behaviour of flexible risers aspirating fluid via their free-hanging end, applied in the offshore industry like the Cold Water Pipe for OTEC.

One of the explanations of the unstable behaviour to occur, is flutter near the free-hanging fluid inlet. The pipe with a certain small initial deflection/excitation relative to its neutral vertical position, causes the fluid to make an angle when entering the pipe. This yield in an exchange of momentum, which can lead to flutter.

I expect the flow near the inlet of the pipe to be of crucial importance and I am looking for ways to gain a better understanding of what is happening with Ansys CFX.

What would be the best approach to tackle this topic? Do you have advises for me?

Thanks in advance.
Berend is offline   Reply With Quote

Old   January 17, 2010, 07:00
Default
  #7
smn
Member
 
Join Date: Jun 2009
Posts: 56
Rep Power: 8
smn is on a distinguished road
hi:
i am intrested in such fields too,but i have a general question:
in the cfx FSI tutorial such as oscilating plate the deformation of the solid domain is important but for the problems mentioned above such as flutter and vibration of pipes deformation is not beeing discusssed and vibration of solid domain is important...how can vibration be modeled in workbench and cfx?
regards
smn is offline   Reply With Quote

Old   January 17, 2010, 17:13
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,651
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
In V12 you have a number of approaches available. It supports rigid body motion through both deforming mesh and immersed bodies (this is a beta feature) - the body stays rigid but moves around and no FEA solver is required. If the body needs to deform then you need to go to FSI where the CFX solver is coupled with the ANSYS FEA solver. This allows the body to deform at the cost of significantly increased solver run time.
ghorrocks is offline   Reply With Quote

Old   January 18, 2010, 07:58
Default
  #9
smn
Member
 
Join Date: Jun 2009
Posts: 56
Rep Power: 8
smn is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
In V12 you have a number of approaches available. It supports rigid body motion through both deforming mesh and immersed bodies (this is a beta feature) - the body stays rigid but moves around and no FEA solver is required. If the body needs to deform then you need to go to FSI where the CFX solver is coupled with the ANSYS FEA solver. This allows the body to deform at the cost of significantly increased solver run time.
Thanks alot for your useful replies.good luck.regards
smn is offline   Reply With Quote

Old   January 18, 2010, 12:05
Default
  #10
Senior Member
 
Join Date: Apr 2009
Posts: 511
Rep Power: 12
stumpy is on a distinguished road
There is a fair bit in the literature for wing flutter. The classic case is the AGARD 445 wing, since experimental data exists. Googling for this returns plenty of info. ANSYS also has an FSI training course.

http://www.ansys.com/services/ts-cou...85&Location=NA
stumpy is offline   Reply With Quote

Old   January 22, 2010, 01:39
Default FSI for shock absorber
  #11
New Member
 
pari
Join Date: Sep 2009
Posts: 5
Rep Power: 7
mallya is on a distinguished road
Hi Glenn,
i am working on 2 way coupled Fluid structure analysis of a twin tube shock absorber using ANSYS12.0 (Mechanical and CFX), and now getting error like......Fatal error in requesting total mesh displacement from structural part. Is any one know the reason behind this, ur answer will be very much helpful for me.....
mallya is offline   Reply With Quote

Old   July 26, 2011, 11:48
Default
  #12
Member
 
Muhammad Amir
Join Date: May 2011
Posts: 31
Rep Power: 6
solomedic is on a distinguished road
hi mallya, I was getting same error some days back,there can be two possible reasons,the first is that your mesh is very distorted,try to map mesh the geometry. and secondly you may have copied the workbench case files here and there, just start a new case and just save it at default location and then dont transfer files here and there
solomedic 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
FSI raj Main CFD Forum 11 October 5, 2012 13:07
Two way FSI and flutter of fan blade Nevel CFX 1 October 6, 2009 17:43
FSI test cases Kirikou Main CFD Forum 8 November 6, 2006 10:49


All times are GMT -4. The time now is 03:23.