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Weak Constraints from COMSOL 3.5 to 4.2a
Posted Jul 15, 2013, 6:01 p.m. EDT MEMS & Nanotechnology, Fluid & Heat, MEMS & Piezoelectric Devices, Microfluidics Version 4.2a 3 Replies
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I have seen many posts regarding this but none had any definite answer.
I am trying to follow a tutorial which involving Stoke's flow, and have the following problems:
1. "Go to Properties of mmglf model and turn Weak constraints -> On and Constraint type -> Nonideal"
I have found out that the mmglf module is the same as spf module of 4.2a with the Stoke's flow check box checked. I have also found out that I can add a "Weak Constraint" node to the spf module. But I don't know if this should be the volume "Weak Contraint" node or the surface one. Also in the node, Contraint type can be set either to "Bidirectional" or "User-defined" (not Unidirectional which is non-ideal). How do I set it to "Nonideal"?
Note: "Nonideal Weak Constraint" is used to automatically calculate the hydrodynamic stress on the particle surface.
2. "Options Menu | Expressions | Boundary Expressions"
How do I write Boundary Expressions? I feel Coupling Variables is to be used, but I am not sure how. I was only able to find Integration/Summation to the boundaries.
Please help. Relevant images are attached.
Attachments:
Hello Gopinath Danda
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Have you figure it out? I am also very interested in this topic. Lemme know if you have made progress, please.
Cheers,
Mao
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I will surely post here if I find out something regarding this. Thanks.
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A little update.
The weak constraints should be applied on the boundaries. If you can select 'non-ideal', select it; if not, the 'non-ideal' is by default (what they say from the documentation).
For the boundary expressions, you can define variables on the corresponding boundaries in "Definition".
Also please lemme know if you have any experience with the remeshing.
Cheers,
Mao