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A structure-preserving numerical method for quasi-incompressible Navier-Stokes-Maxwell-Stefan systems

Aaron Brunk, Ansgar Jüngel, Maria Lukáčová-Medvid'ová

TL;DR

The paper develops a conforming finite element method with mixed explicit-implicit time discretization for the quasi-incompressible Navier–Stokes–Maxwell–Stefan system, ensuring mass preservation, pointwise quasi-incompressibility, and a discrete energy inequality. It provides a rigorous variational formulation, derives discrete identities and a priori bounds, and demonstrates convergence and structure-preserving behavior through two- and three-component 2D experiments, including a relative energy analysis. The work advances numerical analysis and simulation capability for multicomponent, cross-diffusion flows by delivering a robust, energy-stable discretization that respects the coupled physics. This framework lays groundwork for error estimates and higher-order structure-preserving schemes, with potential applications to complex fluids and electrolyte transport problems.

Abstract

A conforming finite element scheme with mixed explicit-implicit time discretization for quasi-incompressible Navier-Stokes-Maxwell-Stefan systems in a bounded domain with periodic boundary conditions is presented. The system consists of the Navier-Stokes equations, together with a quasi-incompressibility constraint, coupled with the cross-diffusion Maxwell-Stefan equations. The numerical scheme preserves the partial masses and the quasi-incompressibility constraint and dissipates the discrete energy. Numerical experiments in two space dimensions illustrate the convergence of the scheme and the structure-preserving properties.

A structure-preserving numerical method for quasi-incompressible Navier-Stokes-Maxwell-Stefan systems

TL;DR

The paper develops a conforming finite element method with mixed explicit-implicit time discretization for the quasi-incompressible Navier–Stokes–Maxwell–Stefan system, ensuring mass preservation, pointwise quasi-incompressibility, and a discrete energy inequality. It provides a rigorous variational formulation, derives discrete identities and a priori bounds, and demonstrates convergence and structure-preserving behavior through two- and three-component 2D experiments, including a relative energy analysis. The work advances numerical analysis and simulation capability for multicomponent, cross-diffusion flows by delivering a robust, energy-stable discretization that respects the coupled physics. This framework lays groundwork for error estimates and higher-order structure-preserving schemes, with potential applications to complex fluids and electrolyte transport problems.

Abstract

A conforming finite element scheme with mixed explicit-implicit time discretization for quasi-incompressible Navier-Stokes-Maxwell-Stefan systems in a bounded domain with periodic boundary conditions is presented. The system consists of the Navier-Stokes equations, together with a quasi-incompressibility constraint, coupled with the cross-diffusion Maxwell-Stefan equations. The numerical scheme preserves the partial masses and the quasi-incompressibility constraint and dissipates the discrete energy. Numerical experiments in two space dimensions illustrate the convergence of the scheme and the structure-preserving properties.

Paper Structure

This paper contains 14 sections, 6 theorems, 55 equations, 5 figures, 2 tables.

Key Result

lemma thmcounterlemma

Equations 1.mass--1.flux, 1.chem--1.incom can be written as 1.mass2--1.divMu for smooth solutions. If $V_i=V>0$ for $i=1,\ldots,N$, equations 1.mom2 and 1.divMu reduce to 1.momim.

Figures (5)

  • Figure 1: Snapshots of the partial mass densities $\rho_1$ (upper row), $\rho_2$ (middle row), and $\rho_3$ (lower row) at times $t=0.001,0.02,0.04,0.06, 0.1,0.5$ for the experiment in Section \ref{['subsec:experiment']}.
  • Figure 2: Snapshots of the total mass density $\rho$ (upper row), velocity magnitude $|\bm{u}|^2$, and pressure $p$ at times $t=0.001,0.02,0.04,0.06,0.1,0.5$ for the experiment in Section \ref{['subsec:experiment']}.
  • Figure 3: Relative energy versus time for the experiment in Section \ref{['subsec:experiment']}.
  • Figure 4: Snapshots of the partial mass densities $\rho_{1}$ (first row), $\rho_2$ (second row), $\rho_3$ (third row) and the total mass density $\rho$ (last row) at times $t=0.1,0.6,1,2$. for the experiment in Section \ref{['subsec:experiment2']}.
  • Figure 5: Relative energy versus time for the experiment in Section \ref{['subsec:experiment2']}.

Theorems & Definitions (14)

  • lemma thmcounterlemma: Reformulation
  • proof
  • lemma thmcounterlemma: Positivity of the mass densities
  • proof
  • lemma thmcounterlemma: Energy identity
  • proof
  • lemma thmcounterlemma: Variational formulation
  • proof
  • theorem 1: Discrete identities
  • proof
  • ...and 4 more