Justification of a Relaxation Approximation for the Navier-Stokes-Cahn-Hilliard System

Fuente: arXiv
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Main Authors: Giesselmann, Jan, Keim, Jens, Leotta, Fabio, Rohde, Christian
Format: Preprint
Published: 2026
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_version_ 1866917223729201152
author Giesselmann, Jan
Keim, Jens
Leotta, Fabio
Rohde, Christian
author_facet Giesselmann, Jan
Keim, Jens
Leotta, Fabio
Rohde, Christian
contents The Navier-Stokes-Cahn-Hilliard (NSCH) system governs the diffuse-interface dynamics of two incompressible and immiscible fluids. We consider a relaxation approximation of the NSCH system that is composed by a system of first-order hyperbolic balance laws and second-order elliptic operators. We prove first that the solutions of an initial boundary value problem for the approximation recover the limiting NSCH system for vanishing relaxation parameters. To cope with the singular limit we exploit the fact that the approximate solutions dissipate an almost quadratic energy, and employ the relative entropy-framework. In the second part of the work we provide numerical evidence for the analytical results, even in flow regimes not covered by the assumptions needed for the theoretical results. Using a novel marker-and-cell conservative finite-difference approach for both the approximation and the limit system, we are able to compute physically relevant interfacial flow problems including Ostwald ripening and high-velocity flow.
format Preprint
id arxiv_https___arxiv_org_abs_2601_18463
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Justification of a Relaxation Approximation for the Navier-Stokes-Cahn-Hilliard System
Giesselmann, Jan
Keim, Jens
Leotta, Fabio
Rohde, Christian
Numerical Analysis
Analysis of PDEs
35L03, 35M11, 65M12, 35Q30
The Navier-Stokes-Cahn-Hilliard (NSCH) system governs the diffuse-interface dynamics of two incompressible and immiscible fluids. We consider a relaxation approximation of the NSCH system that is composed by a system of first-order hyperbolic balance laws and second-order elliptic operators. We prove first that the solutions of an initial boundary value problem for the approximation recover the limiting NSCH system for vanishing relaxation parameters. To cope with the singular limit we exploit the fact that the approximate solutions dissipate an almost quadratic energy, and employ the relative entropy-framework. In the second part of the work we provide numerical evidence for the analytical results, even in flow regimes not covered by the assumptions needed for the theoretical results. Using a novel marker-and-cell conservative finite-difference approach for both the approximation and the limit system, we are able to compute physically relevant interfacial flow problems including Ostwald ripening and high-velocity flow.
title Justification of a Relaxation Approximation for the Navier-Stokes-Cahn-Hilliard System
topic Numerical Analysis
Analysis of PDEs
35L03, 35M11, 65M12, 35Q30
url https://arxiv.org/abs/2601.18463