26. In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is
a) 22.5 m/sec.
b) 33 m/sec.
c) 40 m/sec.
d) 90 m/sec.
Ans: c
27. When the velocity distribution is uniform over the cross-section, the correction factor for momentum is
a) 0
b) 1
c) 4/3
d) 2
Ans: b
28. Least possible value of correction factor for
i) kinetic energy is zero
ii) kinetic energy is 1
iii) momentum is zero
iv) momentum is 1
The correct statements are
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (iv)
d) (ii) and (iv)
Ans: d
29. If the velocity is zero over half of the cross-sectional area and is uniform over the remaining half, then the momentum correction factor is
a) 1
b) 4/3
c) 2
d) 4
Ans: c
30. If velocity is zero over l/3rd of a cross-section and is uniform over remaining 2/3rd of the cross-section, then the correction factor for kinetic energy is
a) 4/3
b) 3/2
c) 9/4
d) 27/8
Ans: c
31. The continuity equation p1V1A1= p2V2A2 is based on the following assumption regarding flow of fluid
a) steady flow
b) uniform flow
c) incompressible flow
d) frictionless flow
where pi and p2 are mass densities.
Ans: a
32. Which of the following velocity potentials satisfies continuity equation ?
a) x2y
b) x2-y2
c) cosx
d) x2 + y2
Ans: b
33. The motion of air mass in a tornado is a
a) free vortex motion
b) forced vortex motion
c) free vortex at center and forced vortex outside
d) forced vortex at center and free vortex outside
Ans: d
34. In a forced vortex motion, the velocity of flow is
a) directly proportional to its radial distance from axis of rotation
b) inversely proportional to its radial distance from the axis of rotation
c) inversely proportional to the square of its radial distance from the axis of rotation
d) directly proportional to the square of its radial distance from the axis of rotation
Ans: a
35. Stream lines and path lines always coincide in case of
a) steady flow
b) laminar flow
c) uniform flow
d) turbulent flow
Ans: a
36. Equation of continuity is based on the principle of conservation of
a) mass
b) energy
c) momentum
d) none of the above
Ans: a
37. In steady flow of a fluid, the total accele ration of any fluid particle
a) can be zero
b) is never zero
c) is always zero
d) is independent of coordinates
Ans: a
38. The pitot tube is used to measure
a) velocity at stagnation point
b) stagnation pressure
c) static pressure
d) dynamic pressure
Ans: b
39. Hot wire anemometer is used to measure
a) discharge
b) velocity of gas
c) pressure intensity of gas
d) pressure intensity of liquid
Ans: b
40. The theoretical value of coefficient of contraction of a sharp edged orifice is
a) 0.611
b) 0.85
c) 0.98
d) 1.00
Ans: a
41. Which of the following is used to measure the discharge ?
a) current meter
b) venturimeter
c) pitot tube
d) hotwire anemometer
Ans: b
42. Select the incorrect statement.
a) The pressure intensity at vena contracta is atmospheric.
b) Contraction is least at vena contracta.
c) Stream lines are parallel throughout the jet at vena contracta.
d) Coefficient of contraction is always less than one.
Ans: c
43. Size of a venturimeter is specified by
a) pipe diameter
b) throat diameter
c) angle of diverging section
d) both pipe diameter as well as throat diameter
Ans: a
44. Due to each end contraction, the discharge of rectangular sharp crested weir is reduced by
a) 5%
b) 10%
c) 15%
d) 20%
Ans: a
45. The discharge through a V- notch varies as
a) H1/2
b) H3’2
c) H5/2
d) H5’4 where H is head.
Ans: c
46. Which of the following is an incorrect statement ?
a) Coefficient of contraction of a venturimeter is unity.
b) Flow nozzle is cheaper than venturimeter but has higher energy loss.
c) Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined.
d) None of the above statement is correct.
Ans: d
47. Coefficient of velocity of venturimeter
a) is independent of Reynolds number
b) decreases with higher Reynolds number
c) is equal to the coefficient of discharge of venturimeter
d) none of the above
Ans: c
48. The pressure at the summit of a syphon is
a) equal to atmospheric
b) less than atmospheric
c) more than atmospheric
d) none of the above
Ans: b
49. Ay between two stream lines represents
a) velocity
b) discharge
c) head
d) pressure
Ans: b
50. Coefficient of velocity for Borda’s mouth piece running full is
a) 0.611
b) 0.707
c) 0.855
d) 1.00
Ans: b