Global-in-time estimates for the 2D one-phase Muskat problem with contact points
Edoardo Bocchi, Ángel Castro, Francisco Gancedo
TL;DR
This work analyzes the global-in-time behavior of the 2D Muskat problem with contact points, modeled in a vessel with vertical walls and a dry region, using Darcy's law. The authors develop a fixed-domain framework via a velocity potential Neumann problem and a carefully constructed diffeomorphism about a stationary state, enabling a bootstrap to higher regularity through elliptic estimates in domains with corners. They introduce an improved energy-dissipation structure that closes the nonlinear estimates and proves exponential decay of the parallel energy for small perturbations around the stationary profile. The analysis extends techniques from Stokes/Navier–Stokes contact-point problems to the more singular Darcy flow, handling arbitrary contact angles in (0,π) without weighting and leveraging corner spectral analysis to control the elliptic problems. The results pave the way for global well-posedness and stability results for Muskat-type interfaces with capillarity and moving contact lines, with a companion paper addressing local well-posedness.
Abstract
In this paper, we study the dynamics of a two-dimensional viscous fluid evolving through a porous medium or a Hele-Shaw cell, driven by gravity and surface tension. A key feature of this study is that the fluid is confined within a vessel with vertical walls and below a dry region. Consequently, the dynamics of the contact points between the vessel, the fluid and the dry region are inherently coupled with the surface evolution. A similar contact scenario was recently analyzed for more regular viscous flows, modeled by the Stokes [GuoTice2018] and Navier-Stokes [GuoTice2024] equations. Here, we adopt the same framework but use the more singular Darcy's law for modeling the flow. We prove global-in-time a priori estimates for solutions initially close to equilibrium. Taking advantage of the Neumann problem solved by the velocity potential, the analysis is carried out in non-weighted $L^2$-based Sobolev spaces and without imposing restrictions on the contact angles.
