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Defining Dirichlet Boundary Conditions on an Imported 3D Object with Apertures in it

.obj file with new geometry: https://www.dropbox.com/s/dds8rm3odg2m7gu/largeAp.obj?dl=0 Here is link to images of fields as well since I can't seem to embed the images properly: https://imgur.com/a/...
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1 vote
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Defining Dirichlet Boundary Conditions on an Imported 3D Object with Apertures in it

We don't need define potential in holes, we can use ...
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6 votes
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NDEigensystem: 1D problem with discontinuous coefficients

Yes, it's possible, we just need to use the documented but seldom-used and (probably) confusing last syntax of NDEigensystem. As discussed in Position of ...
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2 votes

How to solve 2D Heat equation on rectangle with NDSolve?

The code is not working, what is my mistake? You had two minor mistakes. Your Rectangle was wrong Rectangle[{0, a}, {0, b}]. ...
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2 votes

how to make the surface of a 3D region smooth

...
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8 votes

how to make the surface of a 3D region smooth

In order to completeness,here we provide another ways to do this. Thanks @xzczd suggestion。 Related How to graph a solid common to multiple functions MeshFunctions ...
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10 votes
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NDSolve for Laplace equation on disk is not working

3 issues here. You've mixed up polar coordinates and Cartesian coordinates. Since the equation is defined in polar coordinates, the shape of domain of definition is no longer a ...
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4 votes

NDSolve for Laplace equation on disk is not working

It looks like the problem was with the periodic BC and JM's above showed how to handle this periodic BC. This below shows that DSolve can also solve this ...
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2 votes

How to put 2 or 3 NeumannValue conditions?

NeumannValue type boundary conditions may overlap, while DirichletCondition may not overlap. So something like this: ...
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3 votes

FEM Mesh for pipes and tubes

You could use the same approach as advocated in this answer: ...
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1 vote

Why do I see Part::partw error when using NDSolveValue?

This was a bug that's fixed in V13.0 (or earlier).
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7 votes
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How does FindRoot decide if a solution has converged?

Turning my comment into an answer. I am in a rush now, Here are the relevant literature references for the affine covariant Newton solver that is implemented as a method of ...
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1 vote

If or Piecewise dependent coefficients in NDSolveValue

There are examples in the documentation that show how to do this: Have a look at the nonlinear (single material) model on the HeatTransferPDEComponent ref page. Concerning multi-materials you could ...
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2 votes

Documentation of NDSolve`FEM`FEMNintegrate

FEMNIntegrate is not documented because it should be used through NIntegrate. NIntegrate will decide when to call FEMNIntegrate.
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4 votes

Inactive form for PDE and symmetry

Up until version 13.0 the finite element method works with Cartesian coordinates. In 13.1 one can use a truncated cylindrical coordinate for axisymmetric PDEs. It's unlikely that something else will ...
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NDEigensystem returns reversed list of eigenfuctions

As I pointed out in a comment above, this is because of an issue described in the documentation: Ordering of dependent variables. The simplest way to deal with this is to specify the "...
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