Fractional regularity, global persistence, and asymptotic properties of the Boussinesq equations on bounded domains
Mustafa Sencer Aydın, Pranava Chaitanya Jayanti
TL;DR
This work analyzes the 2D Boussinesq equations on bounded domains without thermal diffusion, proving global persistence of strong solutions for a spectrum of initial data regularities using parabolic maximal regularity and initial-time compatibility. The authors establish persistence for $V\times H^1$, $D(A)\times H^2$, and $H^k\times H^k$ data, extend these results to fractional regularity, and derive detailed long-time behavior including sharp asymptotics and a necessary-and-sufficient condition for convergence to stratified steady states. The approach blends Galerkin approximations, maximal regularity estimates, and commutator techniques to propagate regularity across the coupled velocity-density system. These results advance understanding of the long-time dynamics of viscous, non-diffusive Boussinesq flows on bounded domains, with precise regularity and asymptotic characterizations that were previously open in this setting.
Abstract
We address the long-time behavior of the 2D Boussinesq system, which consists of the incompressible Navier-Stokes equations driven by a non-diffusive density. We construct globally persistent solutions on a smooth bounded domain, when the initial data belongs to $(H^k\cap V)\times H^k$ for $k\in\mathbb{N}$ and $H^s\times H^s$ for $0<s<2$. The proofs use parabolic maximal regularity and specific compatibility conditions at the initial time. Additionally, we also deduce various asymptotic properties of the velocity and density in the long-time limit and present a necessary and sufficient condition for the convergence to a steady state.
