Aerospace Engineering Gate 2015 Questions with Answer

Ques 1 GATE 2015

Consider the density and altitude at the base of an isothermal layer in the standard atmosphere to be ρ₁ and h₁, respectively. The density variation with altitude (ρ versus h) in that layer is governed by
(R: specific gas constant, T: temperature, g_o: acceleration due to gravity at sea level)

Ques 2 GATE 2015

For constant free stream velocity and density, a change in lift for a large aspect ratio straight wing, with thin cambered airfoil section at small angles of attack, leads to

Ques 3 GATE 2015

As a candidate for a vertical tail, which one of the following airfoil sections is appropriate?

Ques 4 GATE 2015

The primary purpose of a trailing edge flap is to

Ques 5 GATE 2015

Consider a monoplane wing and a biplane wing with identical airfoil sections, wingspans and incidence angles in identical conditions in a wind tunnel. As compared to the monoplane, the biplane experiences

Ques 6 GATE 2015

Consider a wing of elliptic planform, with its aspect ratio AR→∞ Its lift-curve slope, dC_I/dα=_______

Ques 7 GATE 2015

The Reynolds number, Re is defined as U_αL/ν where L is the length scale for a flow, U_α is its reference velocity and ν is the coefficient of kinematic viscosity. In the laminar boundary layer approximation, comparison of the dimensions of the convection term and the viscous term u ∂u/∂x ν∂²u/∂x² leads to the following relation between the boundary layer thickness δ and Re:

Ques 8 GATE 2015

For a thin flat plate at 2 degrees angle of attack, the pitching moment coefficient about the trailing edge is

Ques 9 GATE 2015

For a thin flat plate at 2 degrees angle of attack, the pitching moment coefficient about the trailing edge is

Ques 10 GATE 2015

The velocity profile of an incompressible laminar boundary layer over a flat plate developing under constant pressure is given by u(y)/U_α=3y/(2δ)-1/2(y/δ)³. The freestream velocity U_∞=10 m/s and the dynamic viscosity of the fluid μ=1.8×10^-skg/(ms) At a streamwise station where the boundary layer thickness δ=5 mm, the wall shear stress is _______ ×10^-3Pa

Ques 11 GATE 2015

Consider a NACA 0012 aerofoil of chord c in a freestream with velocity V_∞ at a non-zero positive angle of attack α. The average time-of-flight for a particle to move from the leading edge to the trailing edge on the suction and pressure sides are t₁ and t₂, respectively. Thin aerofoil theory yields the velocity perturbation to the freestream as -V_x(1+cos θ)α/sin θ on the suction side and as V_x(1+cos θ)α/sin θ on the pressure side, where θ corresponds to the chordwise position, x=c/2(1-cos θ). Then t₂-t₁ is

Ques 12 GATE 2015

Consider a 2-D blunt body in an incompressible fluid stream. The flow is irrotational and can be modeled as a linear combination of a uniform flow and a line source (Rankine half body) as shown below. Let s be the distance of the line source from the front stagnation point. Let d be the upstream distance from the stagnation point to the streamwise location (labeled below as P) where the oncoming stream reaches 90% of its undisturbed velocity. Then d/s=_______

Ques 13 GATE 2015

For a normal shock, the relation between the upstream Mach number (M₁) and the downstream Mach number (M₂) is given by M₂²=((γ-1)M₁²+2)/(2γM₁²+1-γ) For an ideal gas with γ=1.4 the asymptotic value of the downstream Mach number is