On the hydrostatic approximation of 3D Oldroyd-B model
Marius Paicu, Tianyuan Yu, Ning Zhu
TL;DR
This work analyzes the hydrostatic approximation for the 3D Oldroyd-B model in a thin strip, with $\operatorname{Re}=\varepsilon^{-2}$ and $\operatorname{We}=\varepsilon$, establishing global well-posedness of the hydrostatic limit under small analytic-in-$x$ data. It then rigorously justifies the hydrostatic limit from the rescaled Oldroyd-B system to the hydrostatic system, providing an explicit convergence rate by a detailed weighted-energy analysis in anisotropic Sobolev spaces and using phase-based analytic control. The authors derive and bound the velocity and stress-field dynamics, including a nonlinear-terms analysis via para-linearization, to close the estimates. The results supply a rigorous foundation for hydrostatic regimes in viscoelastic fluids and offer a methodological blueprint for singular-limit problems in complex rheological models.
Abstract
In this paper, we study the hydrostatic approximation for the 3D Oldroyd-B model. Firstly, we derive the hydrostatic approximate system for this model and prove the global well-posedness of the limit system with small analytic initial data in horizontal variable. Then we justify the hydrostatic limit strictly from the re-scaled Oldroyd-B model to the hydrostatic Oldroyd-B model and obtain the precise convergence rate.
