This note establishes the blow up estimates near the blow up time for a system of heat equations coupled in the boundary conditions. Under certain assumptions, the exact rate of blow up is established. We also prove that the only solution with vanishing initial values when pq G 1 is the trivial one.
On Critical Exponents for the Heat Equation with a Mixed Nonlinear Dirichlet–Neumann Boundary Condition
✍ Scribed by Bei Hu; Hong-Ming Yin
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 310 KB
- Volume
- 209
- Category
- Article
- ISSN
- 0022-247X
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✦ Synopsis
In this paper we consider the heat equation u s ⌬ u in an unbounded domain t N Ž . ⍀;R with a partly Dirichlet condition u x, t s 0 and a partly Neumann condition u s u p on the boundary, where p ) 1 and is the exterior unit normal on the boundary. It is shown that for a sectorial domain in R 2 and an orthant N Ž . domain in R there exists an explicit critical exponent p ⍀ ) 1 such that all c Ž x positive solutions blow up in finite time when p g 1, p while there exist c positive global solutions if p ) p and initial data are suitably small. All our c blowup results include the critical case.
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