Moving Wall Problem

dreamchaser · October 14, 2014, 01:24

Hello Everyone,

I just need some advice in modeling a moving wall. I attached a picture of my problem set up. I would like to run a simulation where the wall is initially touching the circular surface at one point. The circular surface has some kind of oil on it. Due to the rotation of the circular surface, a pressure will be generated in the gap that will push the wall back. I would like to calculate the new film thickness due to the translation of the wall.

This problem is related to a journal bearing.

I am not familiar with a moving mesh at all and wanted to clarify if this problem fits into this category?

Also, I really have no idea on the software requirements or steps to solve this problem. For example, I am just using Design Modeler and CFX. Is this problem possible to solve with this software? I think I was reading that ICEM can only set this mesh up and it can be solved in CFX. I would appreciate any kind of insight you can provide. If there is a similar tutorial or problem that has been solved, I would be grateful to hear about it.

Thanks!!

ghorrocks · October 14, 2014, 05:55

Modelling a circle which touches a tangent line is horrible as the mesh gets squeezed to oblivion. Things are much easier if you start the circle a small distance away, or if you put a small flat on the circle or some other simplification to eliminate the tangency.

These simplifications also mean you can model this without remeshing.

dreamchaser · October 15, 2014, 12:09

Quote:

Originally Posted by ghorrocks

Modelling a circle which touches a tangent line is horrible as the mesh gets squeezed to oblivion. Things are much easier if you start the circle a small distance away, or if you put a small flat on the circle or some other simplification to eliminate the tangency.

These simplifications also mean you can model this without remeshing.

Hi Glenn,

Yes, I will start the circle a small distance away. To clarify, is it possible to solve this problem in CFX? I have never done something like this. Also, I assume design modeler cannot make this mesh? If you have any resources or advice on where I can read up on doing a moving mesh simulation, I would appreciate it.

ghorrocks · October 15, 2014, 18:10

Yes, you can model it in CFX. Starting a small distance off the tangent line will make things much easier. You can also draw and mesh this in DesignModeller/ANSYS Mesh.

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October 14, 2014, 05:55		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Modelling a circle which touches a tangent line is horrible as the mesh gets squeezed to oblivion. Things are much easier if you start the circle a small distance away, or if you put a small flat on the circle or some other simplification to eliminate the tangency. These simplifications also mean you can model this without remeshing.

October 15, 2014, 18:10		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Yes, you can model it in CFX. Starting a small distance off the tangent line will make things much easier. You can also draw and mesh this in DesignModeller/ANSYS Mesh.