Blow-up Set and Upper Rate Estimate for A Semilinear Heat Equation

Initial blow-up solution of a semilinear heat equation

We study the existence and uniqueness of a maximal solution of equation ut − ∆u + f(u) = 0 in Ω× (0,∞), where Ω is a domain with a non-empty compact boundary, which satisfies u = g on ∂Ω × (0,∞), assuming that g and f are given continuous functions and f is also convex, nondecreasing, f(0) = 0 and verifies Keller-Osserman condition. We show that if the boundary of Ω satisfies the parabolic Wien...

Blow up Dynamic and Upper Bound on the Blow up Rate for critical nonlinear Schrödinger Equation

We consider the critical nonlinear Schrödinger equation iut = −∆u − |u| 4 N u with initial condition u(0, x) = u0 in dimension N . For u0 ∈ H1, local existence in time of solutions on an interval [0, T ) is known, and there exists finite time blow up solutions, that is u0 such that limt→T<+∞ |ux(t)|L2 = +∞. This is the smallest power in the nonlinearity for which blow up occurs, and is critical...

Asymptotic Behaviour and Blow-up of Some Unbounded Solutions for a Semilinear Heat Equation

The initial-boundary value problem for the nonlinear heat equation u, = Au + Xf(u) might possibly have global classical unbounded solutions, u* = u(x, r; uS), for some "critical" initial data u*. The asymptotic behaviour of such solutions is studied, when there exists a unique bounded steady state w(x,A) for some values of L We find, for radial symmetric solutions, that u*(r,t)-*w{r) for any 0 ...

Complete Blow-Up after T,,, for the Solution of a Semilinear Heat Equation

The Blow–up Rate for a Semilinear Parabolic Equation with a Nonlinear Boundary Condition

In this paper we obtain the blow-up rate for positive solutions of ut = uxx−λu, in (0, 1)×(0, T ) with boundary conditions ux(1, t) = uq(1, t), ux(0, t) = 0. If p < 2q − 1 or p = 2q − 1, 0 < λ < q, we find that the behaviour of u is given by u(1, t) ∼ (T − t) − 1 2(q−1) and, if λ < 0 and p ≥ 2q − 1, the blow up rate is given by u(1, t) ∼ (T − t) − 1 p−1 . We also characterize the blow-up profil...