Wave equation with nonhomogenous neumann BC

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Discussion Overview

The discussion centers on finding an analytic solution to the wave equation \( u_{tt} - c^2 u_{xx} = 0 \) under non-homogeneous Neumann boundary conditions, specifically \( u_x(0,t) = A \) for a nonzero constant \( A \). The participants are exploring solutions within a bounded domain (0 to L) and a semi-infinite domain (0 to ∞).

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant requests a specific analytic solution to the wave equation with non-homogeneous Neumann boundary conditions.
  • Another participant provides the general solution \( u = u_1(x - ct) + u_2(x + ct) \) and notes that a single boundary condition is insufficient to determine the arbitrary functions \( u_1 \) and \( u_2 \).
  • A different participant expresses the need for more than just the general solution provided.
  • One participant challenges the initial request by asking if the original poster has attempted to solve the equation themselves.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there is a mix of requests for specific solutions and challenges regarding the adequacy of the information provided.

Contextual Notes

The discussion does not clarify the specific methods or assumptions needed to derive a solution under the given boundary conditions, nor does it address the implications of the non-homogeneity in the boundary conditions.

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I've been searching online for the past week but can't seem to find what I am looking for.

I need the analytic solution to the wave equation: utt - c^2*uxx = 0

with neumann boundary conditions that are not homogeneous, i.e. ux(0,t) = A, for nonzero A.

also, the domain i require the solution to be in is a bounded domain (0 to L) or better yet the semi-infinite domain (0 to ∞)

can anyone refer me to a source?

Thank you
 
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So it's utt - c2uxx = 0
([noparse]utt - c2uxx = 0[/noparse])

The general solution is easy: u = u1(x - c*t) + u2(x + c*t)
for arbitrary functions u1 and u2.
One can find it by changing variables to w1 = x - c*t and w2 = x + c*t

One can see from that solution that a single boundary condition won't be enough to fix u1 and u2. One will need two boundary conditions for that.
 
I need more than the general solution
 
Have you tried solving it yourself?
 

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