Question

What is the value of Cp at stagnation point for a hypersonic body?

(a) 0

(b) 1

(c) 2

(d) Infinite

The question was posed to me in an interview.

This intriguing question originated from Newtonian Theory topic in section Numerical Techniques for Nonlinear Supersonic Flow, Elements of Hypersonic Flow, Couette and Poiseuille Flow of Aerodynamics

Answer 1

The correct option is (c) 2

To explain: According to the Newtonian theory, Cp = 2sin^2 θ. The maximum value for Cp exists at stagnation point where θ = π/2. For this value, the value of Cp is 2. This is contrast to the maximum value of Cp = 1 for an incompressible flow.