# User Portlet

Alexander Trounev
Discussions
It is not so difficult problem for FEM implementations. Please, see my post on https://mathematica.stackexchange.com/questions/214279/3d-elastic-waves-in-a-glass
![Figure 2][5] ![Figure 3][6] Since we have historical conjunction of Jupiter and Saturn I have prepared code with visualization planet Jupiter and Saturn with moons. First code also published [here][3]. Visualization of planet Jupiter: ...
Thank you for your selection. Now I should make a last step to force this code run 10-100 times faster. And then we can incorporate real data to evaluate parameters for every region.
In a current version of Mathematica 12.1 there is no special solver for integrodifferencial equations. [Here][1] we show solver with using Haar wavelets for dynamic system presented in a paper M.A. Khan, A. Atangana, Modeling the dynamics of...
I used the standard code to triangulate the mesh coord = CountryData["USA", "Polygon"][[1, 1, 1]]; bmr = BoundaryMeshRegion[coord, Line[Append[Range[Length[coord]], 1]]]; usatri = TriangulateMesh[bmr, MaxCellMeasure -> .1]; ...
These are routine tests that I did for Mathematica FEM in version 11 using a special time integration algorithm that I am testing. Surprisingly, the tests were passed both in the problem of covection and in the problem of flow around a cylinder...
There is a cylinder, and you use plane geometry. Equation QE is therefore erroneous. You do not use FEM at all. To use FEM, call Needs["NDSolveFEM"], then read the tutorial on a page FEMDocumentation/guide/FiniteElementMethodGuide.
You changed the code and changed the question. My answer now looks out of place. Which question should I answer?
This can be used as a regular analytical solution, for example s = DSolve[{i[t] == Cr vc'[t], vc[t] == vco[t] (1 + m) - Lr i'[t], -(1 + m) i[t] - vco[t]/RL == Co vco'[t], vc[0] == Vcrmax, i[0] == 0, vco[0] == Vo}, {i, vc, ...
To answer this question, we can compare two methods for solving the heat equation: 1) the "MethodOfLines" in which boundary condition Derivative[1, 0][u][5, t] == -h (u[5, t] - u1) is used; and 2) FEM in which boundary condition `NeumannValue[-h...