Question

The area – Mach number relation yields how many solution(s) for a given Mach number?

(a) 1

(b) 2

(c) 3

(d) 0

I got this question in an international level competition.

I'm obligated to ask this question of Nozzles topic in division Quasi-One-Dimensional Flow of Aerodynamics

Answer 1

Correct option is (b) 2

To explain I would say: The area – Mach relation which is the ratio of local area to throat area as a function of Mach number yields two solutions for a given Mach number. One is a subsonic value and the other is the corresponding supersonic value. That value that has to be chosen for a specific Mach number depends on the inlet and exit pressure of the duct.