Global strong solutions with large initial data for the Cauchy problem of the multi-dimensional compressible Navier-Stokes-Korteweg system
Xiangdi Huang, Yongteng Gu, Muxi Lei
TL;DR
This work proves the global existence of strong solutions for the multi-dimensional compressible Navier–Stokes–Korteweg (quantum NSK) system in $\\mathbb{R}^N$ with large initial data, specifically addressing the Cauchy problem for $N=2$ with $\gamma\ge1$ and $N=3$ with $1\le\gamma<8/3$, under strictly positive far-field density. The authors transform to an effective velocity $v = u + \nabla \log\rho$, yielding a parabolic structure, and develop a truncated De Giorgi iteration to obtain a strict density lower bound in the whole space, without symmetry assumptions. They combine Nash–Moser-type iterations for high regularity with Littlewood–Paley techniques to control nonlinearities and derive upper bounds for $\rho$, followed by high-order estimates to achieve global well-posedness. The results constitute the first global strong-solution theory for physically relevant compressible NSK equations in the whole space with large data, advancing understanding of capillarity and quantum-viscous effects in multi-dimensional flows. The methods provide a framework to handle far-field behavior and vacuum tendencies, with potential implications for related capillary models and energy-structure-based analyses.
Abstract
In this paper, we establish global strong solutions for arbitrarily large initial data to the 2D and 3D compressible Navier-Stokes-Korteweg system, also referred to as the quantum Navier-Stokes equations, originally derived by Dunn and Serrin [Arch. Ration. Mech. Anal. 88(2):95-133, 1985]. Specifically, we prove the existence of global strong solutions for arbitrarily large initial data in the case $N=2$ when $γ\ge 1$, and $N=3$ with $1 \le γ< 8/3$ for the associated Cauchy problem. By employing techniques from Littlewood-Paley theory, range truncation analysis, refined Nash-Moser and De Giorgi iteration methods, we derive positive upper and lower bounds for the density. As a consequence, we are able to treat the whole-space case with strictly positive far-field density. To the best of our knowledge, this is the first result that establishes global strong solutions for physically relevant compressible Navier-Stokes equations in the whole space, without imposing any symmetry or special geometric assumptions on the initial data.
