On the $\mathcal R$-boundedness of solution operators for a compressible fluid model of Korteweg type in general domains
Sri Maryani, Miho Murata
TL;DR
The paper addresses the resolvent problem for a compressible Navier-Stokes-Korteweg system with surface tension in general domains. It develops ${\mathcal{R}}$-bounded solution operator families via a localization and parametrix framework, leveraging bent-half-space results and the Weis operator-valued Fourier multiplier theorem to obtain analytic semigroup generation and maximal $L_p$-$L_q$ regularity. This enables robust local solvability theory for the associated nonlinear problem in maximal regularity spaces and provides a pathway to optimal decay and stability analyses. The approach systematically extends known results from the whole space and half-space to uniform $C^3$ domains, including the bent boundary case, by a sequence of reductions and controlled remainder terms, with implications for diffuse-interface fluid models in complex geometries.
Abstract
In this paper, we consider a resolvent problem arising from the free boundary problem for the compressible fluid model of the Korteweg type, which is called the Navier-Stokes-Korteweg system, with surface tension in general domains. The Navier-Stokes-Korteweg system describes the liquid-vapor two-phase flow with non-zero thickness phase boundaries, which is often called the diffuse interface model. Our purpose is to show the solution operator families of the resolvent problem are $\mathcal R$-bounded, which gives us the generation of analytic semigroup and the maximal regularity in the $L_p$-in-time and $L_q$-in-space setting by applying the Weis operator valued Fourier multiplier theorem.
