Questions tagged [boundary-condition-at-infinity]
Tag for differential equations satisfying boundary conditions at infinity, or with open boundary conditions, or defined on an unbounded domain.
191 questions
2 votes
3 answers
247 views
Heat equation with b.c. at $+\infty$ and i.c. at $-\infty$
I am wondering what is the best way to solve numerically a initial-boundary value problem of heat equation like this (surely I've made a lot of mistakes in the code): ...
- 651
2 votes
4 answers
201 views
Using NDSolve to solve three coupled ODEs
I am trying in this code to solve three non-linear ODEs together, and I want to plot the three functions as functions of η. Why does my code not work? ...
- 83
1 vote
0 answers
81 views
Why does the "No Dirichlet condition" warning appear for fine mesh but not for coarse mesh?
It is known that the solution of the Laplace equation with exclusively Neumann boundary conditions is ambiguous. Wolfram Mathematica warns about this by submitting messages like this one: No ...
- 850
1 vote
3 answers
443 views
Greenfunction of 1D Helmholtz Equation
I'm new to Mathematica, and I'd like to find the Green function of the 1D Helmholtz Equation $$ \frac{d^2}{dx^2}u + k^2u=\delta(x-x_0)$$ on the whole x axis. I know that there are a few possible ...
- 111
5 votes
1 answer
291 views
A Boundary Condition That Passes Waves Through
I'm trying to model a wave in a box. 3 sides are reflective and so DirichletCondition[u[t, x, y] == 0 One edge (x=1, 0<y<1)...
- 5,094
6 votes
1 answer
407 views
NDEigensystem gives correct eigenvalues but wrong eigenfunctions
I am trying to reproduce Fig2(b) and 2(c) in this paper by solving Eq2 using NDEigensystem. Eq2 is a coupled ODE given as $[\partial_x+k]B1(x)+\zeta(x)A1(x)=EA1(x)$...
- 5,650
2 votes
1 answer
118 views
Young Laplace equation with shooting method
I am attempting to follow the method outlined in this paper on page 5, where the first step requires solving a 2 point boundary value problem. I have tried using the Shooting Method, but to no avail. ...
- 663
2 votes
1 answer
153 views
Solving two coupled 2nd order differential equations with 5 boundary values [closed]
Suppose I have two 2nd order differential equations: X''[r]+2X'[r]/r = 2(V[r]-u)X[r] V''[r]+2V'[r]/r = X[r]^2 with boundary values ...
