# Tag Info

### Speed up finite element method solver with small features

To solve this problem, we put characteristic scale L=300 and then rescale all geometrical parameters on L, as result we have <...
• 46.3k
1 vote

### Unwanted Oscillation in Solution Occurs When Solving Poisson-Nernst-Planck Equation

As one of the possibly solutions we can decrease accuracy and use explicit method as follows ...
• 46.3k
1 vote
Accepted

### Singularity error when solving Poisson-Nernst-Planck equation

We can use FEM to solve this problem as follows ...
• 46.3k

### How to increase the mesh size in NDsolve

You can do that though a Method option but the exact option dependents on whether the DE is stationary or time dependent: ...
• 40.1k
1 vote
Accepted

### Finite element mesh not resolving small features

A slight increase of the accuracy goal helps: ...
• 40.1k
Accepted

### Finite element method for 3D built-up structures using two materials

welcome back to FEM... The multi material section seems relevant for this. Here is how I'd do it. We start in exactly the same way you did: ...
• 40.1k

### Boundary conditions issue with Laplace equation

In Version 14.0 this works: ...
• 40.1k
Accepted

### Boundary conditions issue with Laplace equation

We can use OpenCascadeLink to generate mesh for this problem as follows (note, we rescale l, r, rs because the solution does not ...
• 46.3k
Accepted

### Numerically solved PDE of Ornsteinâ€“Uhlenbeck process on 2-Simplex violates conservation of probability

The initial condition was inconsistent and needed to exclude the boundary: ...
1 vote

### Boundary conditions issue with Laplace equation

It works if you remove one of the two balls. For example : : ...
• 18.7k

### Numerically solved PDE of Ornsteinâ€“Uhlenbeck process on 2-Simplex violates conservation of probability

Roughly your equation is $$\ \partial_t P =-\left(\frac{3}{2}\ - \ y \right) \ \partial_y \ P \ -\left(\frac{5}{2}-x \right) \partial_x \ P +\frac{1}{2}\Delta \ P \ + \frac{3}{2} \ P$$ by the fact ...
• 3,967
1 vote
Accepted

### SMTShowMesh with additional graphics in SMTRestart session

You did two errors. The "Show"->True option creates a new notebook cell, but it does not return the graphics. "Show"->False is correct in your case. See manual: 2)You have ...
• 881
1 vote

### Negative Jacobian for small finite element in AceFEM

The build in Jacobian check is for your case to restrictive. Received warning can be simply ignored in your case.
• 881
1 vote

### New interpolating function on the mesh from operations on other ones

EvaluateOnElementMesh does what you want to do.
• 40.1k

### Solving a large number of coupled non-linear equations

For this equation it could be better to use implicit difference scheme in combination with FEM as follows ...
• 46.3k
Accepted

### Issue with a Piecewise Diffusion Problem

Change your bc to NeumannValue to force a FiniteElement-solution: ...