ASYMPTOTIC BEHAVIOUR OF A POROUS MEDIUM EQUATION WITH FRACTIONAL DIFFUSION

作者：Caffarelli Luis A^*; Luis Vazquez Juan

来源：Discrete and Continuous Dynamical Systems, 2011, 29(4): 1393-1404.

DOI：10.3934/dcds.2011.29.1393

• Porous medium equation
• fractional Laplacian
• obstacle problem
• asymptotic behavior

We consider a porous medium equation with a nonlocal diffusion effect given by an inverse fractional Laplacian operator. The equation is posed in the whole space R-n. In a previous paper we have found mass-preserving, nonnegative weak solutions of the equation satisfying energy estimates. Here we establish the large-time behaviour. We first find selfsimilar nonnegative solutions by solving an elliptic obstacle problem for the pair pressure-density involving the Laplacian, obtaining what we call obstacle Barenblatt solutions. The theory for elliptic fractional problems with obstacles has been recently established. We then use entropy methods to show that the asymptotic behavior of general finite-mass solutions is described after renormalization by these special solutions, which represent a surprising variation of the Barenblatt profiles of the standard porous medium model.

• 出版日期2011-4