数学物理学报 ›› 2023, Vol. 43 ›› Issue (3): 691-701.

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二维可压缩Prandtl方程倒流点的存在性

邹永辉(),徐鑫*()   

  1. 中国海洋大学数学科学学院 山东青岛 266100
  • 收稿日期:2022-09-27 修回日期:2022-11-28 出版日期:2023-06-26 发布日期:2023-06-01
  • 通讯作者: 徐鑫 E-mail:zouyonghuimath@163.com;xx@ouc.edu.cn
  • 作者简介:邹永辉, E-mail: zouyonghuimath@163.com
  • 基金资助:
    国家自然科学基金(12001506)

Existence of Back-Flow Point for the Two-Dimensional Compressible Prandtl Equation

Zou Yonghui(),Xu Xin*()   

  1. School of Mathematical Sciences, Ocean University of China, Shandong Qingdao 266100
  • Received:2022-09-27 Revised:2022-11-28 Online:2023-06-26 Published:2023-06-01
  • Contact: Xin Xu E-mail:zouyonghuimath@163.com;xx@ouc.edu.cn
  • Supported by:
    NSFC(12001506)

摘要:

该文研究了二维非稳态可压缩Prandtl边界层方程倒流点的存在性, 在Oleinik单调性假设下, 作者首先利用极值原理得到了第一个倒流点如果出现, 那么一定出现在边界$\left\{y=0\right\}$上. 其次, 当压力满足一致逆压梯度条件并且初始值满足一定增长条件时, 作者通过Lyapunov泛函方法得到倒流点的存在性. 最后给出倒流点存在的实例.

关键词: 可压缩Prandtl方程, 倒流点, 极值原理, 逆压梯度, Lyapunov泛函

Abstract:

In this paper, we study the back-flow problem of the two-dimensional unsteady compressible Prandtl boundary layer equations. By using the maximum principle, we obtain that a first back-flow point should appear on the boundary $\left\{y=0\right\}$ if back-flow occurs under Oleinik's monotonicity assumption. Moreover, when the pressure gradient of the outer flow is adverse and the initial velocity satisfies certain growth condition, we obtain the existence of a back-flow point of the compressible Prandtl boundary layer by Lyapunov functional method. Finally, an example of the existence of the back-flow point is given.

Key words: Compressible Prandtl equation, Back-flow point, The maximum principle, Adverse pressure gradient, Lyapunov functional

中图分类号: 

  • O175.29