Basic fluid mechanics - Aerodynamics - Aerospace Engineering Previous Year Questions

1

2007 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2007

An artificial satellite remains in orbit and does not fall to the earth because

A

the centrifugal force acting on it balances the gravitational attraction

B

the on-board rocket motors provide continuous boost to keep it in orbit

C

its transverse velocity keeps it from hitting the earth although it falls continuously

D

due to its high speed it derives sufficient lift from the rarefied atmosphere

Open complete paper

2

2007 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2007

The earth's radius is 6.37×10^6 m and the acceleration due to gravity on its surface is 9.81 m/s^2. A satellite is in a circular orbit at a height of 6.30×10^5 m above the earth's surface. The minimum additional speed it needs to escape from the earth's gravitational field is

A

3.66×10^3 m/s

B

3.12×10^3 m/s

C

3.27×10^3 m/s

D

3.43×10^3 m/s

Open complete paper

3

2007 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2007

The radius of the earth is 6.37×10^6 m and the acceleration due to gravity at its surface is 9.81 m/s^2. A satellite is in circular orbit at a height of 35.9×10^6 m above the earth's surface. This orbit is inclined at 10.5 degrees to the equator. The velocity change needed to make the orbit equatorial is:

A

561 m/s at 84.75 degrees to the initial direction

B

561 m/s at 95.25 degrees to the initial direction

C

281 m/s at 84.75 degrees to the initial direction

D

281 m/s at 95.25 degrees to the initial direction

Open complete paper

4

2007 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2007

For the control volume shown in the figure below, the velocities are measured both at the upstream and the downstream ends. The flow of density \( \rho \) is incompressible, two dimensional and steady. The pressure is \( p_\infty \) over the entire surface of the control volume. The drag on the airfoil is given by,

A

\(\frac{\rho U_\infty^2 h}{3} \)

B

0

C

\(\frac{\rho U_\infty^2 h}{6} \)

D

\(2 \rho U_\infty^2 h \)

Open complete paper

5

2008 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2008

The maximum possible value of pressure coefficient \( C_p \) in incompressible flow is

A

0.5

B

1

C

\(\pi \)

D

\(\infty \)

Open complete paper

6

2008 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2008

An irrotational and inviscid flow can become rotational on passing through a

A

normal shock wave

B

oblique shock wave

C

curved shock wave

D

Mach wave

Open complete paper

7

2008 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2008

A planet is observed to be at its slowest when it is at a distance \( r_1 \) from the sun and at its fastest when it is at a distance \( r_2 \) from the sun. The eccentricity \( e \) of the planet's orbit is given by

A

\(e = \frac{r_1}{r_2} \)

B

\(e = \frac{r_1 - r_2}{r_1 + r_2} \)

C

\(e = \frac{r_2}{r_1} \)

D

\(e = \frac{r_1 + r_2}{r_1 - r_2} \)

Open complete paper

8

2008 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2008

The velocity required for a spacecraft to escape earth's gravitational field depends on

A

the mass of the spacecraft

B

the distance between earth's center and the spacecraft

C

the earth's rotational speed about its own axis

D

the earth's orbital speed

Open complete paper

9

2009 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2009

The acceleration due to gravity on the surface of Mars is 0.385 times that on earth, and the diameter of Mars is 0.532 times that of earth. The ratio of the escape velocity from the surface of Mars to the escape velocity from the surface of earth is approximately

A

0.453

B

0.205

C

0.851

D

0.724

Open complete paper

10

2009 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2009

Consider an ideal flow of density \(\rho\) through a variable area duct as shown in the figure below : Let the cross-sectional areas at sections (1) and (2) be \(A_1\) and \(A_2\) respectively. The velocity measured at section (1) using a Pitot static probe is \(V_1\). Then the static pressure drop \(p_2 - p_1\) is

A

\(-\frac{1}{2} \rho \left( 1 - \frac{A_1^2}{A_2^2} \right) V_1^2\)

B

\(\frac{1}{2} \rho \left( 1 - \frac{A_1^2}{A_2^2} \right) V_1^2\)

C

\(-\frac{1}{2} \rho \left( 1 + \frac{A_1^2}{A_2^2} \right) V_1^2\)

D

\(-\frac{1}{2} \rho \left( 1 - \frac{A_2^2}{A_1^2} \right) V_1^2\)

Open complete paper

11

2010 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2010

A spacecraft of mass 100 kg, moving at an instantaneous speed of \(1.8 \times 10^4\) m/s, picks up interstellar dust at the rate of \(3.2 \times 10^{-8}\) kg/s. Assuming that the dust was initially at rest, the instantaneous rate of retardation of the spacecraft is:

A

\(7.9 \times 10^{-8}\) m/s²

B

\(2.3 \times 10^{-8}\) m/s²

C

zero

D

\(5.8 \times 10^{-8}\) m/s²

Open complete paper

12

2010 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2010

A two stage chemical rocket, having the same specific impulse (\(I_{sp}\)) of 300 s for both the stages is designed in such a way that the payload ratio and the structural ratio are same for both the stages. The second stage of the rocket has following mass distribution : Propellant Mass = 10208 kg Structural Mass = 1134 kg Payload Mass = 1700 kg \(g_0 = 9.8\) m/s² If the rocket is fired from rest and it flies in a zero gravity field and a drag free environment, the final velocity attained by the payload is

A

9729.3 m/s

B

897.3 m/s

C

9360.2 m/s

D

8973.2 m/s

Open complete paper

13

2011 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2011

An impulsive launch of a rocket minimizes the loss of burn-out velocity due to

A

aerodynamic drag force only

B

gravitational force only

C

both aerodynamic drag and gravitational forces

D

reaction jet control force

Open complete paper

14

2011 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2011

A low speed wind tunnel has a contraction ratio of 14:1 and the cross-sectional area of the test section is 1 m². The static pressure difference between the settling chamber and the test section is 40 cm of water column. Assume \( g = 9.81 \text{ m/s}^2 \), \( \rho_{air} = 1.2 \text{ kg/m}^3 \) and \( \rho_{water} = 1000 \text{ kg/m}^3 \). The speed of air in the test section (in m/s) is

Check answer

Open complete paper

15

2012 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2012

The Hohmann ellipse used as earth-Mars transfer orbit has

A

apogee at earth and perigee at Mars.

B

both apogee and perigee at earth.

C

apogee at Mars and perigee at earth.

D

both apogee and perigee at Mars.

Open complete paper

16

2012 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2012

The propellant in a single stage sounding rocket occupies 60% of its initial mass. If all of it is expended instantaneously at an equivalent exhaust velocity of 3000 m/s, what would be the altitude attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at 9.81 m/s².]

A

315 km

B

335 km

C

365 km

D

385 km

Open complete paper

17

2014 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2014

A stationary two stage rocket with initial mass of 16000kg, carrying a payload of 1000kg, is fired in a vertical trajectory from the surface of the earth. Both the stages of the rocket have same specific impulse, I_sp of 300s and same structural coefficient of 0.14. The acceleration due to gravity is 9.8m/s². Neglecting drag and gravity effects and considering both the stages with same payload ratio, the terminal velocity attained by the payload in m/s is ______.

Check answer

Open complete paper

18

2016 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2016

Due to a body in potential flow, the velocity at a point A in the flow field is 20 m/s while the free stream velocity is only 10 m/s. The value of coefficient of pressure (\( C_p \)) at the point A is ______.

Check answer

Open complete paper

19

2016 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2016

The nozzle AB, as shown below, leading to the test section of a low speed subsonic wind tunnel, has a contraction ratio of 10:1. The pressure difference across the nozzle is maintained at 1000 N/m² and the density of air is 1.23 kg/m³. Assuming one-dimensional, steady, inviscid flow, the velocity in the test section as measured at point B is ______ m/s.

Check answer

Open complete paper

20

2017 · Aerospace Engineering · Aerodynamics · Basic fluid mechanics

Aerospace Engineering (AE) 2017

Consider an incompressible flow over a flat plate with the following approximation to the velocity profile: \(\frac{u(y)}{U} = \begin{cases} \frac{y}{\delta} & \text{for } y \leq \delta \\ 1 & \text{for } y > \delta \end{cases}\) where \(\delta\) is the boundary layer thickness and \(U\) the free-stream speed. The normalized momentum thickness (\(\theta/\delta\)) for this profile is __________ (in three decimal places).

Check answer

Open complete paper