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Prescribed mesh displacement in moving mesh models

Posted Jun 5, 2013, 9:27 p.m. EDT Microfluidics Version 4.3a 3 Replies

Laith Hurmez
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Hi All,

Is there a way of applying a prescribed mesh displacement along an edge or a point in 3D when using the laminar, two-phase flow, moving mesh model - tpfmm (Microfluidics module).

The standard velocity and displacement boundary conditions for the deformed mesh apply only to faces rather than edges or points.

Perhaps some way of using weak constraints to achieve this?

Regards,
Laith
3 Replies Last Post Jun 7, 2013, 7:33 p.m. EDT
Vahid Babakeshizadeh
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Posted: 1 decade ago Jun 5, 2013, 9:30 p.m. EDT
You mean that you want to move an edge and not the face?

How does that work?

You mean that you want to move an edge and not the face? How does that work?
Laith Hurmez
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Posted: 1 decade ago Jun 5, 2013, 10:21 p.m. EDT

You mean that you want to move an edge and not the face?

How does that work?


Hi Vahid,

Perhaps I should have put an example. Think of a cube that is being transformed into a sphere due to area minimisation (and surface tension forces). Now imagine that we fix one of the cube faces... the result is (almost) a sphere with one square boundary. Now image that we only fix 3 edges of that same face and letting the remaining edge deform freely, we end up with (almost) a sphere, with 3 square edges and one circular edge. I want to model this type of scenario.

I'm thinking this should be an added constraint on top of the prescribed mesh displacement for a face, e.g. fix dx=0, dy=dz=free and fix 3 edges of the face to dx=0 (already taken care of) and dy=dz=0.

Cheers,
Laith
[QUOTE] You mean that you want to move an edge and not the face? How does that work? [/QUOTE] Hi Vahid, Perhaps I should have put an example. Think of a cube that is being transformed into a sphere due to area minimisation (and surface tension forces). Now imagine that we fix one of the cube faces... the result is (almost) a sphere with one square boundary. Now image that we only fix 3 edges of that same face and letting the remaining edge deform freely, we end up with (almost) a sphere, with 3 square edges and one circular edge. I want to model this type of scenario. I'm thinking this should be an added constraint on top of the prescribed mesh displacement for a face, e.g. fix dx=0, dy=dz=free and fix 3 edges of the face to dx=0 (already taken care of) and dy=dz=0. Cheers, Laith
Vahid Babakeshizadeh
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Posted: 1 decade ago Jun 7, 2013, 7:33 p.m. EDT
I see! Interesting weird shape! :)

You might be able to model your system in a better way to avoid such complexity! I dunno what you're trying to model!
Think about your model from outside and see if you can model it in a way that such constraints don't show up!

Good Luck
I see! Interesting weird shape! :) You might be able to model your system in a better way to avoid such complexity! I dunno what you're trying to model! Think about your model from outside and see if you can model it in a way that such constraints don't show up! Good Luck

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