Correct Answer : Finding pressure coefficient over blunt body
Explanation : Newtonian theory was developed in order to predict the coefficient of pressure over the bluff body when there is incoming flow. It is given by the following relation :
Correct Answer : Hypersonic flow
Explanation : Newton’s theory is more accurate for hypersonic flows with Mach numbers greater than 5. This is because as the free stream Mach number increases and the angle between free stream and inclined flat plate increases, the accuracy of Newtonian theory also increases.
Correct Answer : Increase monotonically
Explanation : The lift/drag ratio for inviscid hypersonic flow over a flat plate is given by :L/D = cotαOn plotting the curve, as the angle of attack decreases, L/D ratio monotonically increases. Obviously this is a hypothetical condition as skin friction drag is not incorporated in this.
Correct Answer : Cp = 2sin2θ
Explaination : 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 = 2sin2θWhere, θ is the local inclination angle of the surface with respect to the free stream velocity.
Correct Answer : Tangential momentum
Explanation : When there is an incoming stream of particles on a flat plate with a free stream velocity, the normal momentum is transferred to the surface after the impact. On the other hand, the tangential momentum is preserved. This result was obtained by Newton with an assumption that the particles do not interact with each other and hence are linear.
Correct Answer : 0
Explanation : The Newtonian model for fluid flow is only able to predict the coefficient of pressure in the frontal region of the surface where the free stream impacts the body. The portion which does not experience any impact from the incoming flow is known to be in the shadow which has zero (0) coefficient of pressure.
Correct Answer : 54.7 deg
Explanation : According to the Newton’s theory, the coefficient of lift is given by :cl = 2sin3αThis value is maximum for α = 54.7 degrees.
Correct Answer : Pitching moment coefficient
Explanation : Chemically reactive flow in hypersonic flow determines the pitching moment over the space shuttle. The pressure on the forward part of the shuttle body is usually higher for a chemically reactive gas, and it is lower in the rearward part. This leads to a positive pitching moment of the shuttle.
Correct Answer : Oblique shock method
Explanation : There are three other local surface inclination inclinations, in addition to Newtonian theory. Methods that are widely used to estimate distributions of pressure over hypersonic bodies are the tangent wedge method, tangent cone method and shock – expansion method.
Correct Answer : False
Explanation : For three – dimensional bodies such as a cone, Newtonian theory is generally more accurate in contrast with two – dimensional bodies like wedge. One more important property to note is that Newton’s theory gets much more accurate with increasing Mach number.
