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 Andrew.Coughtrie July 27, 2011 15:38

FSI Mesh stiffness

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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

 ghorrocks July 27, 2011 19:01

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.

 Andrew.Coughtrie July 27, 2011 19:26

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

 mvoss July 29, 2011 03:50

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

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