Question

The definitions of P0 and ρ0 involve______

(a) Isothermal compression

(b) Isentropic compression

(c) Adiabatic compression

(d) Any process gives the same value

I had been asked this question during an interview.

I'd like to ask this question from The Basic Normal Shock Equations in section Normal Shock Waves of Aerodynamics

Answer 1

The correct option is (b) Isentropic compression

Explanation: The defined properties of the flow  P0 and ρ0 involve isentropic compression, which is adiabatic and reversible both. These properties are the values of the flow parameters when the flow is isentropically compressed to zero velocity, at a point with properties P and ρ.