Question

What is the relation according to the Newton’s theory for hypersonic problems?

(a) Cp = 2sinθ

(b) Cp = 2sin^2θ

(c) Cp = cosθ

(d) Cp = 2sinθcosθ

The question was asked in a national level competition.

This is a very interesting question from Time-Marching Technique topic in portion Time-Marching Technique of Aerodynamics

Answer 1

Correct choice is (b) Cp = 2sin^2θ

Easy explanation: By using the relation of oblique shock theory and applying the limits M∞ → ∞ because hypersonic flows theoretically range from Mach number = 5 to infinity and γ → 1, we get the result for Newtonian theory. It is given by:

Cp = 2sin^2θ

Where, θ is the local inclination angle of the surface with respect to the free stream velocity.