The zero capillarity limit for the Euler-Korteweg system with no-flux boundary conditions
Paolo Antonelli, Yuri Cacchiò
TL;DR
This work analyzes the vanishing capillarity limit for the Euler-Korteweg system with no-flux boundary conditions on bounded domains. It develops a relative-entropy framework to prove convergence of finite-energy weak solutions to strong Euler solutions, while addressing boundary-layer effects through a high-order augmented entropy and a boundary-layer correction. The authors extend prior relative-entropy results from periodic settings to nontrivial boundaries and provide detailed remainder estimates that accommodate gradient information, yielding convergence for both the basic variables and their first-order derivatives under suitable scaling of the boundary layer. The results offer a robust approach to singular limits with nontrivial boundaries and connect to quantum hydrodynamics and semiclassical limits via augmented energy formulations.
Abstract
In this article, we study the small dispersion limit of the Euler-Korteweg system in a bounded domain with no-flux boundary conditions. We exploit a relative entropy approach to study the convergence of finite energy weak solutions towards strong solutions to the compressible Euler system. Since we consider non-trivial boundary conditions, our approach needs a correction for the limiting particle density, due to the appearance of a (weak) boundary layer. We believe this approach can be adapted to study similar singular limits involving non-trivial boundary conditions.
