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Usage of Total Mesh Displacement in CEL for Movement Computation

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Old   August 30, 2016, 08:32
Default Usage of Total Mesh Displacement in CEL for Movement Computation
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Hi,
I'm trying to solve a bending case, causing problems with mesh stiffness. . For visualization: 2 is bending and the subdomains 1 should move downwards according to the Total mesh displacement.


In 2D the application of:
Code:
maxVal( Total Mesh Displacement Y  )@REGION:FSI_y_2
is fine for adjusting the connected subdomain.

Coming to my question: If I'm trying this in 3D, there are curved shapes leading to unsuitable shifting values for the subdomains. Is there a possible way for copying the movement of a 3D area to another?

Thanks in advance
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Old   August 30, 2016, 20:54
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You could use the probe function to get the displacement at one point and use it to define the motion of another boundary or subdomain.

In 3D for complex shapes I would consider using the default mesh displacement diffusion method.
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Old   August 31, 2016, 01:41
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Hi,
thanks for your input. I am actually using the displacement diffusion method (but with a value function). The problem is the stiffness. Due to the small gaps and close walls (my bending geometry as well as the enclosing one) none of the built-in settings works properly. Thats why I'm stuck with this workaround. The outer region 1 needs to be moved downwards so the inner one can be deformed with a suitable stiffness. I enclosed part of my example studies with deformations.
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Old   September 2, 2016, 03:39
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Hi,
sorry for double posting ...

I start again with a motion undefined region close to my moving element and with an enclosing domain, that I'll force to move. As the second picture clearly shows: one problem is the continuity of movement. Is it somehow possible to take the Mesh Displacement Y of an edge (with a named selection for addressing) and create a CEL / UDF function (close to the probe thing ghorrocks mentioned) and create a function dependant on a coordinate (lets say x) for application as a movement input?

Someone did something like this?
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Old   September 2, 2016, 07:13
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If you can't get the mesh deformation stuff working you can do dynamic remeshing. The tip of your device covers quite a large size range and dynamic remeshing would help here.

Having said that I think with some careful planning you should be able to get this working with mesh deformation only. Have you considered a GGI at the end of the paddle so the mesh at the end hardly moves, but the paddle can slide up and down with a GGI?
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Old   September 2, 2016, 07:37
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Quote:
Originally Posted by ghorrocks View Post
If you can't get the mesh deformation stuff working you can do dynamic remeshing. The tip of your device covers quite a large size range and dynamic remeshing would help here.
As I plan to implement 2way FSI, additional dynamic remeshing is quite time consuming ...

Quote:
Originally Posted by ghorrocks View Post
Having said that I think with some careful planning you should be able to get this working with mesh deformation only. Have you considered a GGI at the end of the paddle so the mesh at the end hardly moves, but the paddle can slide up and down with a GGI?
Currently I don't use interfaces ... I thought about the sliding of meshes but didn't manage to get it working correctly so far
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