Acta mathematica scientia,Series B ›› 2022, Vol. 42 ›› Issue (4): 1569-1584.doi: 10.1007/s10473-022-0416-1

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TWO DIMENSIONAL SUBSONIC AND SUBSONIC-SONIC SPIRAL FLOWS OUTSIDE A POROUS BODY

Shangkun WENG, Zihao ZHANG   

  1. School of Mathematics and Statistics, Wuhan University, Wuhan, 430072, China
  • Received:2021-03-04 Revised:2021-05-23 Online:2022-08-25 Published:2022-08-23
  • Contact: Zihao ZHANG,E-mail:zhangzihao@whu.edu.cn E-mail:zhangzihao@whu.edu.cn
  • Supported by:
    The first author is partially supported by National Natural Science Foundation of China (11701431, 11971307, 12071359).

Abstract: In this paper, we investigate two dimensional subsonic and subsonic-sonic spiral flows outside a porous body. The existence and uniqueness of the subsonic spiral flow are obtained via variational formulation, which tends to a given radially symmetric subsonic spiral flow at far field. The optimal decay rate at far field is also derived by Kelvin’s transformation and some elliptic estimates. By extracting spiral subsonic solutions as the approximate sequences, we obtain the spiral subsonic-sonic limit solution by utilizing the compensated compactness. The main ingredients of our analysis are methods of calculus of variations, the theory of second-order quasilinear equations and the compensated compactness framework.

Key words: Subsonic spiral flows, Euler equations, subsonic-sonic limit, a porous body

CLC Number: 

  • 35B40
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