A review on two types of sonic interfaces

TL;DR

This paper reviews two types of sonic interfaces in fluid dynamics, highlighting their differences and presenting an open problem related to decelerating transonic flows governed by the Euler-Poisson system.

Contribution

It provides a comparative analysis of sonic interfaces in different flow regimes and introduces an open problem in the context of steady Euler-Poisson flows.

Findings

Sonic interfaces as weak discontinuities in shock configurations

Sonic interfaces as regular interfaces in transonic flows

Discussion of an open problem in decelerating transonic solutions

Abstract

In this paper, two examples of sonic interfaces are presented. The first example shows the case of sonic interfaces as weak discontinuities in self-similar shock configurations of unsteady Euler system. The second example shows the case of sonic interfaces as regular interfaces in accelerating transonic flows governed by the steady Euler-Poisson system with self-generated electric forces. And, we discuss analytic differences of the two examples, and introduce an open problem on decelerating transonic solution to the steady Euler-Poisson system.