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Asymptotic stability threshold of the 2-D monotone shear flow with no-slip boundary condition

Zhen Li, Shunlin Shen, Zhifei Zhang

Abstract

In this paper, we investigate the asymptotic stability threshold problem for the 2-D Navier-Stokes equations in a finite channel with no-slip boundary conditions, around monotone shear flow $(U(t,y),0)$. We establish that the flow is asymptotically stable under perturbations satisfying $\|u^{\mathrm{in}}\|_{H^2}\leq cν^{\frac12}$. To achieve the stability threshold $ν^{\frac{1}{2}}$, the key ingredients of the proof include: sharp resolvent estimates for the vorticity based on weak-type resolvent bounds; weighted space-time estimates for the vorticity; pointwise estimates for the velocity. Furthermore, we handle the nonlinear term through a divergence formulation, which facilitates the sharp application of the aforementioned space-time estimates.

Asymptotic stability threshold of the 2-D monotone shear flow with no-slip boundary condition

Abstract

In this paper, we investigate the asymptotic stability threshold problem for the 2-D Navier-Stokes equations in a finite channel with no-slip boundary conditions, around monotone shear flow . We establish that the flow is asymptotically stable under perturbations satisfying . To achieve the stability threshold , the key ingredients of the proof include: sharp resolvent estimates for the vorticity based on weak-type resolvent bounds; weighted space-time estimates for the vorticity; pointwise estimates for the velocity. Furthermore, we handle the nonlinear term through a divergence formulation, which facilitates the sharp application of the aforementioned space-time estimates.
Paper Structure (11 sections, 15 theorems, 207 equations)

This paper contains 11 sections, 15 theorems, 207 equations.

Key Result

Theorem 1.1

Let $(\omega,\psi)$ be the solution to equ: omli11. There exist positive constants $\nu_0$, $\epsilon_{0}$ and $c$, such that if the initial perturbation satisfies $\|u^{\mathrm{in}}\|_{H^2}\leq c\nu^{\frac{1}{2}}$, $0<\nu\leq \nu_{0}$, then the solution $(\omega,u)$ satisfies the global stability e where the stability norm is given by with $f_k(t,y)=:\int_{\mathbb{T}} f(t,x,y) e^{-ikx}dx$. Here,

Theorems & Definitions (27)

  • Theorem 1.1
  • Lemma 2.1
  • Proposition 2.2
  • Lemma 2.3: Weak-type resolvent estimates
  • proof
  • Lemma 2.4
  • proof
  • proof : Proof of Proposition \ref{['lemma:non-slip boundary,resolvent']}
  • Proposition 3.1
  • Proposition 3.2
  • ...and 17 more