On the quenching set for a fast diffusion equation: regional quenching

2005 ◽  
Vol 135 (3) ◽  
pp. 585-602
Author(s):  
R. Ferreira ◽  
A. de Pablo ◽  
F. Quirós ◽  
J. D. Rossi
Keyword(s):  
Boundary Condition ◽  
Diffusion Equation ◽  
Blow Up ◽  
Single Point ◽  
Fast Diffusion ◽  
Fast Diffusion Equation ◽  
Flux Boundary Condition ◽  
Bounded Interval ◽  
Quenching Set ◽  
Type Boundary

We study positive solutions of a very fast diffusion equation, ut = (um−1ux)x, m < 0, in a bounded interval, 0 < x < L, with a quenching-type boundary condition at one end, u (0, t) = (T − t)1/(1 − m) and a zero-flux boundary condition at the other, (um −1ux)(L, t) = 0. We prove that for m ≥ −1 regional quenching is not possible: the quenching set is either a single point or the whole interval. Conversely, if m < −1 single-point quenching is impossible, and quenching is either regional or global. For some lengths the above facts depend on the initial data. The results are obtained by studying the corresponding blow-up problem for the variable v = um −1.

On the quenching set for a fast diffusion equation: regional quenching

2005 ◽  
Vol 135 (3) ◽  
pp. 585-602
Author(s):  
R. Ferreira ◽  
A. de Pablo ◽  
F. Quirós ◽  
J. D. Rossi
Keyword(s):  
Boundary Condition ◽  
Diffusion Equation ◽  
Blow Up ◽  
Single Point ◽  
Fast Diffusion ◽  
Fast Diffusion Equation ◽  
Flux Boundary Condition ◽  
Bounded Interval ◽  
Quenching Set ◽  
Type Boundary

We study positive solutions of a very fast diffusion equation, ut = (um−1ux)x, m < 0, in a bounded interval, 0 < x < L, with a quenching-type boundary condition at one end, u (0, t) = (T − t)1/(1 − m) and a zero-flux boundary condition at the other, (um −1ux)(L, t) = 0. We prove that for m ≥ −1 regional quenching is not possible: the quenching set is either a single point or the whole interval. Conversely, if m < −1 single-point quenching is impossible, and quenching is either regional or global. For some lengths the above facts depend on the initial data. The results are obtained by studying the corresponding blow-up problem for the variable v = um −1.

scholarly journals Spatial Profile of the Dead Core for the Fast Diffusion Equation with Dependent Coefficient

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Zhengce Zhang ◽  
Biao Wang
Keyword(s):  
Maximum Principle ◽  
Diffusion Equation ◽  
Single Point ◽  
Fast Diffusion ◽  
Spatial Profile ◽  
Fast Diffusion Equation ◽  
Dead Core ◽  
Core Profile ◽  
The Dead ◽  
Core Problem

We consider the dead-core problem for the fast diffusion equation with spatially dependent coefficient and obtain precise estimates on the single-point final dead-core profile. The proofs rely on maximum principle and require much delicate computation.

scholarly journals Non-Self-Similar Dead-Core Rate for the Fast Diffusion Equation with Dependent Coefficient

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Liping Zhu ◽  
Zhengce Zhang
Keyword(s):  
Diffusion Equation ◽  
Single Point ◽  
Fast Diffusion ◽  
Fast Diffusion Equation ◽  
Dead Core ◽  
Core Profile ◽  
Self Similar ◽  
Similar Solutions ◽  
Compactness Arguments ◽  
Core Problem

We consider the dead-core problem for the fast diffusion equation with spatially dependent coefficient and show that the temporal dead-core rate is non-self-similar. The proof is based on the standard compactness arguments with the uniqueness of the self-similar solutions and the precise estimates on the single-point final dead-core profile.

scholarly journals Extinction and Nonextinction for the Fast Diffusion Equation

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Chunlai Mu ◽  
Li Yan ◽  
Yi-bin Xiao
Keyword(s):  
Boundary Condition ◽  
Weak Solution ◽  
Initial Data ◽  
Diffusion Equation ◽  
Dirichlet Boundary ◽  
Fast Diffusion ◽  
First Eigenvalue ◽  
Homogeneous Dirichlet Boundary Condition ◽  
Fast Diffusion Equation ◽  
The First Eigenvalue

This paper deals with the extinction and nonextinction properties of the fast diffusion equation of homogeneous Dirichlet boundary condition in a bounded domain ofRNwithN>2. For0<m<1, under appropriate hypotheses, we show thatm=pis the critical exponent of extinction for the weak solution. Furthermore, we prove that the solution either extinct or nonextinct in finite time depends strongly on the initial data and the first eigenvalue of-Δwith homogeneous Dirichlet boundary.

scholarly journals Uniqueness and time oscillating behaviour of finite points blow-up solutions of the fast diffusion equation

2019 ◽  
Vol 150 (6) ◽  
pp. 2849-2870
Author(s):  
Kin Ming Hui
Keyword(s):  
Initial Data ◽  
Diffusion Equation ◽  
Bounded Domain ◽  
Positive Constant ◽  
Blow Up ◽  
Fast Diffusion ◽  
Bounded Domains ◽  
Fast Diffusion Equation

AbstractLet n ⩾ 3 and 0 < m < (n − 2)/n. We extend the results of Vazquez and Winkler (2011, J. Evol. Equ. 11, no. 3, 725–742) and prove the uniqueness of finite points blow-up solutions of the fast diffusion equation ut = Δum in both bounded domains and ℝn × (0, ∞). We also construct initial data such that the corresponding solution of the fast diffusion equation in bounded domain oscillates between infinity and some positive constant as t → ∞.

scholarly journals Numerical quenching versus blow-up for a nonlinear parabolic equation with nonlinear boundary outflux

2020 ◽  
pp. 151-171
Author(s):  
Kouakou Cyrille N'dri ◽  
Kidjegbo Augustin Toure ◽  
Gozo Yoro
Keyword(s):  
Boundary Condition ◽  
Original Problem ◽  
Nonlinear Boundary ◽  
Blow Up ◽  
Heat Equations ◽  
Quenching Rate ◽  
Flux Boundary Condition ◽  
Bounded Interval ◽  
Nonlinear Parabolic ◽  
Quenching Time

In this paper, we study numerical approximations for positive solutions of a semilinear heat equations, $u_{t}=u_{xx}+u^{p}$, in a bounded interval $(0,1)$, with a nonlinear flux boundary condition at the boundary $u_{x}(0,t)=0$, $u_{x}(1,t)=-u^{-q}(1,t)$. By a semi-discretization using finite difference method, we get a system of ordinary differential equations which is expected to be an approximation of the original problem. We obtain some conditions under which the positive solution of our system quenches or blows up in a finite time and estimate its semidiscrete blow-up and quenching time. We also estimate the semidiscrete blow-up and quenching rate. Finally, we give some numerical results to illustrate our analysis.

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