What is the coefficient of pressure at minimum pressure point a function of?

Length of the airfoil

Critical Mach number

Freestream Mach number

Chord/thickness ratio of airfoil

Correct Answer : Critical Mach number

Explanation : Coefficient of pressure at minimum pressure point which is present at the upper surface of the airfoil is given by the relation :

In this the value of gamma is constant depending on the medium. The only varying quantity is critical Mach number. Thus, the coefficient of pressure at minimum pressure point is a function of only critical Mach number.

Recently Updated in Aerodynamics Questions

Under which condition do we get the detached shock wave on a cone?

θ_c = 0

θ_c = infinty

θ_c = θ_cmax

θ_c > θ_cmax

Correct Answer : Option (D) : θ_c > θ_cmax

Explaination : For a given freestream Mach number M_∞, there exists a maximum cone angle for which if we go beyond that value, the shock wave originating at the cone’s vertex gets detached. Thus, the condition for detached shock wave is θ_c > θ_cmax.

What is the relation between maximum allowed cone angle and wedge angle for attached shock wave?

(θ_max)_wedge = (θ_max)_cone

(θ_max)_wedge > (θ_max)_cone

(θ_max)_wedge < (θ_max)_cone

(θ_max)_wedge ≈ (θ_max)_cone

Correct Answer : Option (B) : (θ_max)_wedge > (θ_max)_cone

Explaination : Due to the three-dimensional relieving effect, for a particular freestream Mach number, the maximum cone angle allowed is larger than the maximum wedge angle before the shock wave becomes detached.

Where does the flow remain supersonic in a conical surface?

Between the oblique shock and the sonic line

Between the sonic line and the conical surface

Flow is not supersonic beyond the oblique shock

Between the oblique shock and the conical surface

Correct Answer : Option (A) : Between the oblique shock and the sonic line

Explanation : The incoming flow over a cone is mostly supersonic between the surface of the cone and the oblique shock wave. Except in some cases when the half cone angle is large, flow sometimes becomes subsonic and one of the rays originating the cone’s vertex acts at the sonic line. The flow between the sonic line and the oblique shock thus remains supersonic.