Aerodynamics
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Aerodynamics...
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Code No: 07A42101 Set No. 1 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.Tech. II Sem., I Mid-Term Examinations, March – 2010 AERODYNAMICS-1 Objective Exam Name: ______________________________ ______________________________ Hall Ticket No. Answer All Questions. All Questions Carry Equal Marks.Time: 20 Min. Marks: 20. I
Choose the correct alternative:
1. For a NACA airfoil, the leading edge is (A) Sharp (B) elliptical (C) an arc of a circle (D) an intersection of the upper and lower surface contours 2. Reynold’s number is defined as (A) Inertia force / elastic force
[
]
[
]
(D) Inertia force / viscous force
4. A flow of air has a velocity V and vorticity, ξ. If the flow is irrotational, the relationship between the two is given by ∇
[ (B) Viscous force / inertia force
(C) √ (Inertia force / elastic force)
(B) ξ =
]
(D) Inertia force / viscous force
3. Mach number is defined as (A) Inertia force / elastic force
∇
[ (B) Viscous force / inertia force
(C) √(Inertia force / elastic force)
(A) ξ = V x
]
xV
(C) V =
∇ x
ξ
(D) ξ =
∇
.V
5. In the context of flow over an airfoil, Kutta condition states that (A) velocity at the leading edge is zero (B) velocity at the trailing edge is zero (C) velocity of flow from the upper and lower surfaces at the trailing edge are equal (D) the velocity is maximum at the leading edge
[
]
6. A combination of uniform flow and a doublet give a __________ [ ] flow over a right circular cylinder. (A) lifting (B) rankine rankine oval oval (C) semi-infinite body (D) non-lifting non-lifting flow over a right circular cylinder. 7. The nomenclature being Γ = circulation, V= free stream velocity,
[
R = radius of the right circular cylinder, and the condition being Γ > 4 π circular cylinder has stagnation points __________ (A) one on the body (B) two on the body (C) one in the flow outside the body D) two in the flow outside the body
V R , the flow over the
8. Kutta - Zhukovsky (Kutta – Joukowski) transformation transforms a circle into an airfoil. The equation is transforms into (A) a straight line
]
[
]
. Radius of the circle is ‘a’. If a > b, the circle
(B) an ellipse (C) a symmetric airfoil
(D) a cambered airfoil
Cont….2
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Code No:
07A42101
:2:
Set No. 1
9. Time rate of change of circulation around a closed curve consisting of the same fluid element, equals (A) zero
[
]
10. The distance between centre of pressure and the quarter chord point for a symmetric airfoil is [ (A) zero (B) lift-independent (C) minimum (D) maximum
]
II
(B) one
(C) minus one (D) infinity
Fill in the blanks:
11. The enthalpy of a gas
_________
(Explain the symbols used).
12. The magnitude and units of Gas constant for air are
__________
(Explain the symbols used).
13. Combination of uniform flow with source s ource and sink gives _________ 14. If
ψ is
the stream function, following the terminology of J.D. Anderson, the components of velocity
along the Cartesian coordinates are given by
__________
(Explain the symbols used).
15. The speed of sound is given by c = ____________ ____________ (Explain the symbols used).
16. The four different types of drag are ________ 17. The skin friction drag of an airfoil in inviscid flow is _________ 18. The Kutta - Zhukovsky (Kutta – Joukowski) transformation transforms a circle into a flat plate if ___ 19. The Kutta - Zhukovsky (Kutta – Joukowski) transformation transforms a circle into a cambered airfoil if _________ 20. The most important limitation of the thin airfoil theory is that the ________
-oOo-
Code No: Set No. 1 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.Tech. II Sem., I Mid-Term Examinations, Jan/Feb– 2011 AERODYNAMICS – I Objective Exam Name: ______________________________ Hall Ticket No. A
Answer All Questions. All Questions Carry Equal Marks.Time: 20 Min. Marks: 10. I
Choose the correct alternative:
1.
Continuity equation for a fluid is (A)
2.
3.
(B)
(C)
[
]
[
]
[
]
[
]
[
]
(D)
Momentum equation in the X – direction is (A)
(B)
(C)
(D)
The energy equation is (A) (B) (C) (D)
4.
For an irrotational flow, the vorticity is (A)
5.
(B) zero
(C) 2
=0
(D)
=0
The thickness of boundary layer over a flat plate in laminar flow with Reynolds no. Re is (A)
(B)
(C)
(D)
6.
The number of stagnation points on a sphere in an inviscid flow is (A) zero (B) one (C) two (D) indeterminate
[
]
7.
Euler’s equation is (A) (B)
[
]
[
]
8. 9.
(C)
The lift slope for a thin airfoil is (A) (B) (C) 3
(D) (D)
In the case of a boundary layer the momentum thickness is given by (A)
10.
dp =
(B)
(C)
[
]
(D)
In the case of an airfoil the lift force is (A) along the chord (B) along the free stream (C) normal to the chord (D) normal to the free stream direction
[
]
Cont…..2
Code No:
:2:
Set No. 1
II
Fill in the blanks:
11.
Continuity equation for a steady, incompressible, inviscid two dimensional flow ………….
12.
Displacement thickness signifies the missing …………………
13.
In a velocity field, the vorticity is
14.
The drag over a cylinder in an inviscid uniform flow is ----------------
15.
Kelvin’s circulation theorem states that ……………………
16.
The circulation at the trailing edge of an airfoil is ……………….
17.
The lift of an airfoil in a flow of circulation Γ is given by ……………….
18.
If an inviscid flow over a cylinder, Γ = 4 π V R , the number of stagnation points on the cylinder is ……………..
19.
Boundary layer separates from a thin airfoil if the angle of attack is ………………..
20.
Magnus effect is …………………….
and the angular velocity is .
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Code No: 54040
Set No. 1 AERODYNAMICS – I Keys
I
Choose the correct alternative:
1)
A
2)
B
3)
A
4)
B
5)
D
6)
C
7)
B
8)
B
9)
A
10)
D
II
Fill in the blanks:
11) 12)
mass;
13)
ξ = 2 ω
14)
zero.
15) 16)
zero.
17)
ρ V Γ
18)
one.
19)
very high.
20)
occurrence of lift over a spinning sphere in a viscous flow.
-oOo-
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Code No: 54040 Set No. 1 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.Tech. II Sem., I Mid-Term Examinations, February – 2012 AERODYNAMICS-I Objective Exam Name: ______________________________ Hall Ticket No. Answer All Questions. All Questions Carry Equal Marks. Time: 20 Min. Marks: 10. I
Choose the correct alternative:
1.
For the airfoils with positive camber, the value of 0
a)-2 or -3 2.
3.
0
(b) -4 or -5
K sin t
(b)
K sin θ
(b) ds × ∂V = 0
0
0
(c)
2π sin θ K
r
2
⎛ V ⎞ ⎟ ⎝ V ∞ ⎠
b) Cp = 1 − ⎜
Continuity equation for a fluid is D ρ D ρ v a) + ρ ∇.V = 0 b) + ∇. ρ V = 0 Dt Dt
⎛ V ∞ ⎞ ⎟ ⎝ V ⎠
D ρ Dt
[
]
[
]
[
]
[
]
[
]
[
]
[
]
[
]
[
]
0
−
2π sin θ K
r
(d) ds × V ≠ 0
2
c) Cp = 1 − ⎜
c)
]
(d) wave drag
(d)
(c) ds × V = 0
2
[
(d) 4 or5
Pressure coefficient for incompressible inviscid flow is given by
⎛ V ⎞ ⎟ ⎝ V ∞ ⎠
7.
−
2π r 2π r The equation of a streamline is given by
a) Cp = 1 + ⎜ 6.
0
(c) 2 or 3
For a doublet ψ =
a) ds.V = 0 5.
0
The drag produced due to the flow separation on an airfoil is a)Skin friction drag (b) pressure drag (c) base drag
a)
4.
0
will be of order
+ ∇. ρ V = 0
⎛ V ∞ ⎞ ⎟ ⎝ V ⎠
2
d) Cp = 1 + ⎜
d)
D ρ v Dt
+ ρ ∇.V = 0
Momentum equation in the Y– direction is
∂ ( ρ v ) ∂ ( ρ v ) ∂p ∂p + ∇. ( ρ vV ) = − + ρ f y + Fy viscous b) + ∇. ( ρ uV ) = − + ρ f y + Fy viscous ∂t ∂y ∂t ∂y ∂ ( ρ v ) ∂p ∂ ρ ∂ p c) + ρ∇.V = − + ρ f y + F y viscous d) + ∇. ρ v.V = − + ρ f y + Fy viscous ∂t ∂y ∂t ∂y a)
8.
The lift slope for a thin airfoil is (a) π
9.
(d)
π 2
Kelvin’s circulation theorem states that a)
10.
(c) 3π
(b) 2π
DΓ Dt
≠ 0
(b)
DΓ Dt
=0
(c)
DΓ Dt
Product of stream lines and equi-potential lines is a)1
(b)
(c) 0
= 1
(d)
DΓ Dt
= −1
(d) – 1
Cont….2
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Code No: 54040
:2:
Set No. 1
II
Fill in the blanks:
11.
The maximum value of lift coefficient, Cl, occurs just prior to the __________
12.
An airfoil with chord of 0.64 m is in an airstream at sea level conditions. The free stream velocity is 70 m/s and lift per unit span is 1254 N/m The value of the lift coefficient Cl = __________
13.
An adverse pressure gradient is a region where the pressure ____________ in the flow direction.
14.
For a symmetric airfoil the location of center of pressure is at ______________.
15.
For the vortex flow, velocity potential, φ = _____________
16.
Non-lifting flow over a cylinder can be obtained from a combination of ____________ and ____________.
17.
is called condition of __________________.
18.
For a rotational flow, the vorticity is ____________.
19.
Continuity equation for a steady, incompressible, inviscid two dimensional flow______________
20.
Bernoulli’s equation is applicable to_____________________ flows only.
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Code No: 54040
Set No. 1
I
AERODYNAMICS-I Keys Choose the correct alternative:
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
A B B C B A A B B D
II
Fill in the blanks:
11. 12. 13. 14.
Stall 0.65 Increases Quarter- chord point
15. 16. 17. 18.
−
Γ
θ
2π Uniform flow and doublet Incompressibility 0
19. 20.
Inviscid incompressible
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Code No: 54040 Set No. 1 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD II B.Tech. II Sem., I Mid-Term Examinations, February – 2013 AERODYNAMICS-I Objective Exam Name: ______________________________ Hall Ticket No. Answer All Questions. All Questions Carry Equal Marks. Time: 20 Min. Marks: 10. I
Choose the correct alternative:
1.
Significance of Non-dimensional analysis a)To remove out Geometry effects c)Both A & B
[
]
b)To incorporate Geometry effects d)To remove dimensional effects
2.
Non conservation form of conservation equations are derived by using a)Eulerian Analysis b)Lagrangian Analysis c)Any of these two
3.
Transport Phenomenon includes following [ ] a)Mass diffusion b)Viscosity c)Thermal diffusion and momentum diffusion d)Thermal diffusion and momentum diffusion & Mass diffusion
4.
In Moving control volume concentration is laid on a)Mass crossing control volume b)Changes in the volume
c)Both
[ ] d)None of the above
[ d)None
]
5.
Rotating flow in concentric circles is called Vortex flow. Then it is a)Incompressible and Inviscid b)Only Inviscid c)Inviscid, Incompressible and Irrotioanl all through the flow d)Inviscid, Incompressible and Irrotioanl except at origin
[
]
6.
Geometry surface of the aerodynamic object senses a)Static pressure at all points c)Static pressure at all points except 2 locations
[
]
b)Stagnation pressure only d)None of the above
7.
Bernoulli’s equation is applied for [ ] a)Incompressible flows only b)Inviscid and Incompressible flows only c)Inviscid Compressible and Incompressible flows d)Inviscid Incompressible and rotational flows
8.
Maximum possible pressure coefficient of Non-lifting flow over cylinder is a)One b)Two c)Three d)Four
[
]
9.
For the flow over circular cylinder, flow gets separated with two stable vortices for a)40
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