Steady compressible radially symmetric flows with nonzero angular velocity in an annulus

JOURNAL OF DIFFERENTIAL EQUATIONS

卷:286

Article

Weng, Shangkun¹  Xin, Zhouping²  Yuan, Hongwei² 

[1] Wuhan Univ, Sch Math & Stat, Wuhan 430072, Hubei, Peoples R China

[2] Chinese Univ Hong Kong, Inst Math Sci, Shatin, Hong Kong, Peoples R China

关键词: Steady Euler system;    Angular velocity;    Smooth transonic flows;    Transonic shock;   

DOI  :  10.1016/j.jde.2021.03.028

来源: Elsevier

【 摘 要 】

In this paper, we investigate steady inviscid compressible flows with radial symmetry in an annulus. The major concerns are transonic flows with or without shocks. One of the main motivations is to elucidate the role played by the angular velocity in the structure of steady inviscid compressible flows. We give a complete classification of flow patterns in terms of boundary conditions at the inner and outer circle. Due to the nonzero angular velocity, many new flow patterns will appear. There exists accelerating or decelerating smooth transonic flows in an annulus satisfying one side boundary conditions at the inner or outer circle with all sonic points being nonexceptional and noncharacteristically degenerate. More importantly, it is found that besides the well-known supersonic-subsonic shock in a divergent nozzle as in the case without angular velocity, there exists a supersonic-supersonic shock solution, where the downstream state may change smoothly from supersonic to subsonic. Furthermore, there exists a supersonic-sonic shock solution where the shock circle and the sonic circle coincide, which is new and interesting. (C) 2021 Elsevier Inc. All rights reserved.

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