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Power of infinity, NDSolve

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  • Subject: [mg128400] Power of infinity, NDSolve
  • From: grasley at
  • Date: Tue, 16 Oct 2012 03:21:56 -0400 (EDT)
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Dear All:

I am trying to solve the 1-D heat equation with NDSolve in cylindrical coords (radial flow only).  The boundary conditions are a fixed outer temperature at r=1 and a zero flux at r=0, with an initial condition of a constant temperature. Unfortunately, I am getting a power of infinity error.  Here is the code:

NDSolve[{D[T[r, t], t] == 1/r*D[r D[T[r, t], r], r],
  Derivative[1, 0][T][0, t] == 0, T[1, t] == 20, T[r, 0] == 0}, T, {r,
   0, 1}, {t, 0, 10}]

Infinity::indet: Indeterminate expression 0. ComplexInfinity encountered. >>

Power::infy: Infinite expression 1/0. encountered. >>

Infinity::indet: Indeterminate expression 0. ComplexInfinity encountered. >>

NDSolve::ndnum: Encountered non-numerical value for a derivative at t == 0.`. >>

I have tried using non-zero initial radial points and nonzero initial times, but to no avail.  Any ideas?

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