Global well-posedness of 3D two-fluid type model with vacuum: smallness on scaling invariant quantity
Huanyao Wen, Chanxin Xie
TL;DR
This work addresses the global well-posedness of a 3D viscous compressible two-fluid model with vacuum, where the pressure depends on two densities and the system is strongly coupled. The authors introduce a scaling-invariant combination of initial data and derive uniform a priori estimates, including a bound on $ th{P}^2$ and $ th{P}^3$, via the effective viscous flux and Zlotnik-type bounds for the densities. Under a smallness condition on this invariant quantity, they prove the existence and uniqueness of global strong solutions, without density domination assumptions. The results extend the understanding of multi-fluid models in vacuum regimes and provide a robust framework for handling pressure-velocity-density interactions in 3D.
Abstract
This paper focuses on Cauchy problem for the three-dimensional two-fluid type model, in which the presence of vacuum is permitted. Under some assumptions that the initial data satisfy appropriate regularity conditions and a compatibility constraint, and that the newly introduced scaling-invariant initial quantities $\bar P^{\frac{ 3}γ} \left(\|\sqrt{ρ_0}u_0\|_{L^2}^2+\|P_0\|_{L^1}\right) \left(\|\nabla u_0\|_{L^2}^2+\|P_0\|_{L^2}^2\right)$ and $\bar P^{\frac{6}γ+1} \left(\|\sqrt{ρ_0}u_0\|_{L^2}^2+\|P_0\|_{L^1}\right)^3 \left(\|\nabla u_0\|_{L^2}^2+\|P_0\|_{L^2}^2\right)$ are sufficiently small, the global well-posedness of strong solutions to the two-fluid type model is derived.
