Compressible subsonic potential flow past a 2D given sharp angular unbounded domain

In this paper, we focus on the two-dimensional subsonic flow problem around an infinite long ramp. The flow is assumed to be steady, isentropic and irrotational, namely, the movement of the flow is described by a second elliptic equation. By the use of a separation variable method, Strum-Liouville theorem and scaling technique, we show that a nontrivial subsonic flow around the infinite long ramp does not exist under some certain assumptions on the potential flow with a low Mach number.