The Verigin problem with phase transition as a Wasserstein flow
Anna Kubin, Tim Laux, Alice Marveggio
TL;DR
The paper reframes the Verigin problem with phase transition as a Wasserstein gradient flow and constructs weak solutions via a time-discrete minimizing movements scheme. The energy functional combines a surface term, a density-dependent bulk energy, and a phase-coupling term, producing an energy–dissipation structure that drives the analysis. The main result is the existence of distributional solutions (ρ,χ,u) that satisfy a transport equation, a weak Young–Laplace interface condition, and an energy-dissipation balance; with d ≥ 3 and uniform Muckenhoupt weights, χ becomes the indicator of a finite-perimeter set in the positively dense region, enabling perimeter convergence. This variational approach provides a rigorous link between mass diffusion, phase transition, and free-boundary dynamics, yielding strong compactness and BV control that are essential for the mathematical well-posedness of this coupled PDE-free boundary problem.
Abstract
We study the modeling of a compressible two-phase flow in a porous medium. The governing free boundary problem is known as the Verigin problem with phase transition. We introduce a novel variational framework to construct weak solutions. Our approach reveals the gradient-flow structure of the system by adopting a minimizing movement scheme using the Wasserstein distance. We prove the convergence of the scheme, obtaining ``relaxed" distributional solutions in the limit that satisfy an optimal energy-dissipation rate. Under the additional assumptions that $d \geq 3$ and that the discrete mass densities are uniformly Muckenhoupt weights, we show that the limit is the characteristic function of a set of finite perimeter in the region where there is no vacuum.
