Spreading and vanishing in nonlinear diffusion problems with free boundaries

By Yihong Du, Bendong Lou. 2013

303 citations recorded by the source corpus.

We study nonlinear diffusion problems of the form $u_t=u_{xx}+f(u)$ with free boundaries. Such problems may be used to describe the spreading of a biological or chemical species, with the free boundary representing the expanding front. For special $f(u)$ of the Fisher-KPP type, the problem was investigated by Du and Lin [8]. Here we consider much more general nonlinear terms. For any $f(u)$ which is $C^1$ and satisfies $f(0)=0$, we show that the omega limit set $\omega(u)$ of every bounded positive solution is determined by a stationary solution. For monostable, bistable and combustion types of nonlinearities, we obtain a rather complete description of the long-time dynamical behavior of the problem; moreover, by introducing a parameter $\sigma$ in the initial data, we reveal a threshold value $\sigma^*$ such that spreading ($\lim_{t\to\infty}u= 1$) happens when $\sigma>\sigma^*$, vanishing ($\lim_{t\to\infty}u=0$) happens when $\sigma<\sigma^*$, and at the threshold value $\sigma^*$, $\omega(u)$ is different for the three different types of nonlinearities. When spreading happens, we make use of "semi-waves" to determine the asymptotic spreading speed of the front.

Subfields: Modeling and Simulation, Molecular Biology, Public Health, Environmental and Occupational Health

View Paper: https://www.semanticscholar.org/paper/72c845250e82ab6ce79d3f0deb1971a696716311

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In Modeling and Simulation

  1. Mingxin Wang
  2. Yang Zhang
  3. Yihong Du
  4. Wan-Tong Li
  5. Yonggang Zhao
  6. Chang-Hong Wu
  7. Zhigui Lin
  8. Jong-Shenq Guo

In Molecular Biology

  1. Mingxin Wang
  2. Yonggang Zhao
  3. Chang-Hong Wu
  4. Yang Zhang
  5. Yihong Du

In Public Health, Environmental and Occupational Health

  1. Mingxin Wang
  2. Yihong Du
  3. Yang Zhang
  4. Yonggang Zhao
  5. Wan-Tong Li
  6. Chang-Hong Wu
  7. Zhigui Lin
  8. Jong-Shenq Guo

Citations in the corpus