数学物理学报 ›› 2023, Vol. 43 ›› Issue (4): 1133-1148.

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外区域上非稳恒Navier-Stokes流的加权模估计

张庆华()   

  1. 南通大学理学院 江苏南通 226019
  • 收稿日期:2022-05-10 修回日期:2023-04-24 出版日期:2023-08-26 发布日期:2023-07-03
  • 作者简介:张庆华, E-mail: zhangqh@ntu.edu.cn

On Weighted Estimates for the Nnonstationary 3D Navier-Stokes Flow in an Exterior Domain

Zhang Qinghua()   

  1. School of Science, Nantong University, Jiangsu Nantong 226019
  • Received:2022-05-10 Revised:2023-04-24 Online:2023-08-26 Published:2023-07-03

摘要:

该文研究外区域上3维非稳恒Navier-Stokes流的加权模估计. 首先构造一个向量场去点乘Navier-Stokes方程的两边, 从而将Navier-Stokes流表示为一个积分方程的强解; 然后对积分方程的各项进行估计. 利用初始条件$|x|^{\alpha}u_{0}\in L^{r}(\Omega)$, $u_{0}\in L_{\sigma}^{3}(\Omega)$, 其中$\|u_{0}\|_{3}$充分小, 指数$0<\alpha<3$, 1<r<3且$\max \left\{r, \frac{3}{2}\right\}<q<\infty$满足适当的条件, 该文推导出加权估计式$\||x|^{\alpha}u(t)\|_{q}\leq C(1+t^{\frac{\alpha}{2}})t^{-\frac{3}{2}(\frac{1}{r}-\frac{1}{q})}$, 其中$t>0$. 在情形$0<\alpha\leq2$下, 该文的初始条件要比文献弱, 对指数$q$的限制也比文献宽松.

关键词: 外区域, Navier-Stokes流, 加权模估计

Abstract:

This paper studies weighted estimates for the 3D Navier-Stokes flow in an exterior domain. By multiplying the Navier-Stokes equation with a well selected vector field, an integral equation is derived, from which we prove that $\||x|^{\alpha}u(t)\|_{q}\leq C(1+t^{\frac{\alpha}{2}})t^{-\frac{3}{2}(\frac{1}{r}-\frac{1}{q})}$ for all $t>0$ under the initial condition $|x|^{\alpha}u_{0}\in L^{r}(\Omega)$ and $u_{0}\in L_{\sigma}^{3}(\Omega)$ with sufficiently small norm $\|u_{0}\|_{3}$, where $0<\alpha<3$, $1$0<\alpha\leq2$ and restriction on $q$ is weaker.

Key words: exterior domain, Navier-Stokes flow, weighted estimate

中图分类号: 

  • O175.24