Power of infinity, NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg128400] Power of infinity, NDSolve
- From: grasley at gmail.com
- Date: Tue, 16 Oct 2012 03:21:56 -0400 (EDT)
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- Delivered-to: l-mathgroup@wolfram.com
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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?