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

FSI Mesh stiffness

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 27, 2011, 15:38
Default FSI Mesh stiffness
  #1
New Member
 
Andrew Coughtrie
Join Date: May 2011
Posts: 27
Rep Power: 5
Andrew.Coughtrie is on a distinguished road
Hi

Does anyone have any suggestions on good CEL expressions to use in defining mesh stiffness? The problem is 2D heart valve opening with a symmetry plane up the middle. I've implemented an expression that increases stiffness near the walls but this has no effect with regards to the symmetry plane which is causing the cells on that boundary to deform significantly.

This is my current expression:

1000[m^5 s^-1]/(max(0.1[mm],Wall Distance)^3)

This allows the mesh around the leaflet to remain relatively un-deformed but then most of the deformation occurs in one cell on the symmetry plane. I've attached a picture to show what is happening.

Any suggestions would be appreciated

Andy
Attached Images
File Type: jpg Boundary Mesh Deformation.jpg (43.5 KB, 72 views)
Andrew.Coughtrie is offline   Reply With Quote

Old   July 27, 2011, 19:01
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,107
Rep Power: 79
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
CFX V14 has some new stuff for mesh stiffness. It may be of interest. You can download a beta version on the CFX Community site.
ghorrocks is offline   Reply With Quote

Old   July 27, 2011, 19:26
Default
  #3
New Member
 
Andrew Coughtrie
Join Date: May 2011
Posts: 27
Rep Power: 5
Andrew.Coughtrie is on a distinguished road
Hi Glenn

Sadly as i'm a student i'm limited to the software the university provides which in this case is only 12.1. They also don't allow us access to the Ansys Portal so i'm limited in where i can get hold of info. Do you know if there is any documentation on these improvements that may help me with ideas? if so i may be able to persuade those who have access at the university to get them for me.

Also you don't know of any threads or papers relating to the topic that could help me do you?

Thanks

Andy
Andrew.Coughtrie is offline   Reply With Quote

Old   July 29, 2011, 03:50
Default
  #4
Senior Member
 
Matthias Voß
Join Date: Mar 2009
Location: Berlin, Germany
Posts: 425
Rep Power: 10
mvoss is on a distinguished road
How about
(1000[m^5 s^-1]/(max(0.1[mm],Wall Distance)^3))+f(x)

with f(x) being smth. like

-2*(min(x/0.001[m],1))^3+3*(min(x/0.001[m],1))^2
(should create a smooth transition)

to make it also dependent from the x-Coord. / the position of the symmetry.

neewbie
mvoss 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
[ICEM] Negative volume error in hybrid mesh siw ANSYS Meshing & Geometry 4 September 3, 2014 05:25
external flow with snappyHexMesh chelvistero OpenFOAM 11 January 15, 2010 20:43
Convergence moving mesh lr103476 OpenFOAM Running, Solving & CFD 30 November 19, 2007 15:09
Mesh Stiffness Option for Mesh Deformation Ste_Lakey CFX 3 January 19, 2006 17:33
How to control Minximum mesh space? hung FLUENT 7 April 18, 2005 09:38


All times are GMT -4. The time now is 12:06.