scholarly journals Fully discrete positivity-preserving and energy-dissipating schemes for aggregation-diffusion equations with a gradient-flow structure

2020 ◽  
Vol 18 (5) ◽  
pp. 1259-1303 ◽  
Author(s):  
Rafael Bailo ◽  
José A. Carrillo ◽  
Jingwei Hu
Keyword(s):  
Flow Structure ◽  
Gradient Flow ◽  
Diffusion Equations ◽  
Positivity Preserving ◽  
Fully Discrete

scholarly journals Convergence of a fully discrete and energy-dissipating finite-volume scheme for aggregation-diffusion equations

2020 ◽  
Vol 30 (13) ◽  
pp. 2487-2522
Author(s):  
Rafael Bailo ◽  
José A. Carrillo ◽  
Hideki Murakawa ◽  
Markus Schmidtchen
Keyword(s):  
Finite Volume ◽  
Flow Structure ◽  
Gradient Flow ◽  
Diffusion Equations ◽  
Finite Volume Scheme ◽  
Time Step ◽  
Discrete Energy ◽  
Volume Scheme ◽  
Fully Discrete ◽  
Local Aggregation

We study an implicit finite-volume scheme for nonlinear, non-local aggregation-diffusion equations which exhibit a gradient-flow structure, recently introduced in [R. Bailo, J. A. Carrillo and J. Hu, Fully discrete positivity-preserving and energy-dissipating schemes for aggregation-diffusion equations with a gradient flow structure, arXiv:1811.11502 ]. Crucially, this scheme keeps the dissipation property of an associated fully discrete energy, and does so unconditionally with respect to the time step. Our main contribution in this work is to show the convergence of the method under suitable assumptions on the diffusion functions and potentials involved.

scholarly journals A Minimizing Movement approach to a class of scalar reaction-diffusion equations

2020 ◽  
Author(s):  
Florentine Catharina Fleißner
Keyword(s):  
General Setting ◽  
Gradient Flow ◽  
Reaction Diffusion ◽  
Reaction Diffusion Equations ◽  
Diffusion Equations ◽  
Step Size ◽  
Time Step ◽  
Flux Boundary Condition ◽  
Time Step Size ◽  
Kantorovich Distance

The purpose of this paper is to introduce a Minimizing Movement approach to scalar reaction-diffusion equations of the form \partial_t u \ = \ \Lambda\cdot \mathrm{div}[u(\nabla F'(u) + \nabla V)] \ - \ \Sigma\cdot (F'(u) + V) u, \quad \text{ in } (0, +\infty)\times\Omega, with parameters $\Lambda, \Sigma > 0$ and no-flux boundary condition u(\nabla F'(u) + \nabla V)\cdot {\sf n} \ = \ 0, \quad \text{ on } (0, +\infty)\times\partial\Omega, which is built on their gradient-flow-like structure in the space $\mathcal{M}(\bar{\Omega})$ of finite nonnegative Radon measures on $\bar{\Omega}\subset\xR^d$, endowed with the recently introduced Hellinger-Kantorovich distance $\HK_{\Lambda, \Sigma}$. It is proved that, under natural general assumptions on $F: [0, +\infty)\to\xR$ and $V:\bar{\Omega}\to\xR$, the Minimizing Movement scheme \mu_\tau^0:=u_0\mathscr{L}^d \in\mathcal{M}(\bar{\Omega}), \quad \mu_\tau^n \text{ is a minimizer for } \mathcal{E}(\cdot)+\frac{1}{2\tau}\HK_{\Lambda, \Sigma}(\cdot, \mu_\tau^{n-1})^2, \ n\in\xN, for \mathcal{E}: \mathcal{M}(\bar{\Omega}) \to (-\infty, +\infty], \ \mathcal{E}(\mu):= \begin{cases} \int_\Omega{[F(u(x))+V(x)u(x)]\xdif x} &\text{ if } \mu=u\mathscr{L}^d, \\ +\infty &\text{ else}, \end{cases} yields weak solutions to the above equation as the discrete time step size $\tau\downarrow 0$. Moreover, a superdifferentiability property of the Hellinger-Kantorovich distance $\HK_{\Lambda, \Sigma}$, which will play an important role in this context, is established in the general setting of a separable Hilbert space.

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