On a finite-volume approximation of a diffusion-convection equation with a multiplicative stochastic force
Caroline Bauzet, Kerstin Schmitz, Aleksandra Zimmermann
TL;DR
The paper analyzes a diffusion-convection SPDE with multiplicative noise on a bounded domain under Neumann conditions and proposes a semi-implicit finite-volume scheme using upwind for the convection and TPFA for diffusion. By combining time-discretization techniques for SPDEs with deterministic spatial discretization tools, it achieves strong convergence of both right- and left-time approximations to the unique variational solution, without relying on stochastic compactness arguments. The convergence is established in $L^p(0,T;L^2(\Omega;L^2(\Lambda)))$ for all finite $p\ge1$ in dimensions $d=2$ and $3$, with $g(u)$ and $\beta(u)$ identified in the limit, and the approach handles the convection term and multiplicative noise in a robust, implementable framework. This work advances numerical analysis for SPDEs by providing a structure-preserving, convergence-guaranteed scheme that can be extended to broader nonlinear flux settings and higher dimensions, enhancing reliability of simulations in stochastic diffusion-convection models.
Abstract
We address an original approach for the convergence analysis of a finite-volume scheme for the approximation of a stochastic diffusion-convection equation with multiplicative noise in a bounded domain of $\mathbb{R}^d$ (with $d=2$ or $3$) and with homogeneous Neumann boundary conditions. The idea behind our approach is to avoid using the stochastic compactness method. We study a numerical scheme that is semi-implicit in time and in which the convection and the diffusion terms are respectively approximated by means of an upwind scheme and the so called two-point flux approximation scheme (TPFA). By adapting well-known methods for the time discretization of stochastic PDEs and combining them with deterministic techniques applied to spatial discretization, we show strong convergence of our scheme towards the unique variational solution of the continuous problem in $L^p(0,T;L^2(Ω;L^2(Λ)))$, for any finite $p\geq 1$.
