Entropy-dissipative discretization of nonlinear diffusion equations and discrete Beckner inequalities

Claire Chainais-Hillairet (1, 2) , Ansgar Jüngel (3) , Stefan Schuchnigg (3)

1 RAPSODI - Reliable numerical approximations of dissipative systems
2 LPP - Laboratoire Paul Painlevé - UMR 8524
3 TU Wien - Vienna University of Technology = Technische Universität Wien

The time decay of fully discrete finite-volume approximations of porous-medium and fast-diffusion equations with Neumann or periodic boundary conditions is proved in the entropy sense. The algebraic or exponential decay rates are computed explicitly. In particular, the numerical scheme dissipates all zeroth-order entropies which are dissipated by the continuous equation. The proofs are based on novel continuous and discrete generalized Beckner inequalities. Furthermore, the exponential decay of some first-order entropies is proved in the continuous and discrete case using systematic integration by parts. Numerical experiments in one and two space dimensions illustrate the theoretical results and indicate that some restrictions on the parameters seem to be only technical.

Domaines: Analyse numérique [math.NA]

Claire Chainais-Hillairet, Ansgar Jüngel, Stefan Schuchnigg. Entropy-dissipative discretization of nonlinear diffusion equations and discrete Beckner inequalities. ESAIM: Mathematical Modelling and Numerical Analysis, 2016, 50 (1), pp.135-162. ⟨10.1051/m2an/2015031⟩. ⟨hal-00924282v2⟩