FLUID DYNAMICS; THE ENERGY EQUATION
1) Due to gravity, the velocity at (b) as compared to that at (a) in figure (1) must be:
a) smaller b) larger c) equal
a
Q=Constant
b
Fig (1)
2) Due to gravity, the pressure at (b) as compared to that at (a) in figure (1) must be:
a) smaller b) larger c) equal
3) If the fluid in the pipe shown in figure (1) is compressible (ρ ∞ pressure) then
the velocity at (b) as compared to that at (a) must be:
a) smaller b) larger c) equal
4) A tank has a water level of 25.0 m above a random datum feeds a pipeline AB
ending at B with an outlet of 4.0 cm diameter. T h e p i p e AB h as a di a m et e r
o f 15.0 cm with point A 20.0 m above the datum and point B at the datum. Find:
a) The discharge through the pipeline and the pressures and water velocities at A & B.
b) If friction losses in the nozzle are 0.5 m, and between A & B are 5.0 m, solve
(a) and plot the hydraulic gradient line and total energy line.
5) Relative to the Total Energy Line, the Hydraulic Gradient Line may not fall:
a) above b) coincide c) below
6) For any orifice, which of the following statements is
correct: a) Cv ≥ 1.0 b) Cv > 1.0 c) Cv <
1.0 d) Cv ≤ 1.0
7) Water issues from a 10.0 cm diameter circular sharp edged orifice under a head of
12.0 m. If a volume of 13.6 m3 is collected in 3 minutes, and the diameter of the jet
at the venacontracta is 8.0 cm, then the values for Cd , Cv & Cc are:
a) 0.64, 0.8 and 0.8 b) 0.63, 0.64 and 0.98 c) 0.51, 0.8 and 0.64
8) Water flows steadily (assumed ideal fluid) from a large b
tank and exits through a constant diameter vertical pipe Fig
as shown in Fig. (2). The air in the tank is pressurized (2) 50
to 50 kN/m2. The height (h) to which water rises is: KN/m2
h
a) 3.1 m b) 7.1 m c) 50 m d) 35 m Air
Water
9) The water velocity in the vertical pipe in figure (2) is:
2m
a) 30.7 m/s b) 7.8 m/s c) 4.6 m/s d) 2.1 m/s
1
, 10) In figure (2), pressure at (a) as compared to pressure at (b) is:
a) smaller b) larger c) equal
11) The velocity of water in a pipe of 10.0 cm diameter is 3.0 m/s. The nozzle at the
end of the pipe has a velocity coefficient of 0.98. If the pressure in the pipe is
0.7 kg/cm2, find the jet diameter, the rate of flow, and the power lost due to
friction in the nozzle.
12) A 5.0-cm diameter orifice (Cd = 0.6) discharges water
from tank A to tank B as shown in fig (3). The reading in the Air Fig (3)
vacuum gauge in tank B is 0.65 Kg/cm2 below atmospheric 2m Oil
- 0.65
pressure, and the air pressure (0.8)
Kg/cm2
above the oil in tank A is 70 KN/m2 , find the discharge from the
orifice and the distance (L). Water
2m
5m 1m
13) In figure (3), if the vacuum gauge reads 0.3 Kg/cm2 instead of L
0.65 Kg/cm2, the pressure change would cause the discharge
through the orifice to:
a) Increase b) decrease c) remain the same
14) A convergent-divergent nozzle is fitted to the side of a water tank, which discharges
7.0 lit/s to the atmosphere where the head on the nozzle is 1.8 m. The exit has a diameter of
4.06 cm, the water vapor pressure is 0.5 m absolute and the height of water in the
barometer is 10.33 m. Neglecting the losses in the convergent part of the nozzle, the
coefficient of discharge Cd and the minimum diameter at the throat of the nozzle Dmin would
be:
a) Cd= 0.91 Dmin=2.53cm b) Cd= 0.81 Dmin=2.53cm c) Cd= 0.91 Dmin=2.43cm
15) Figures (4) and (5) are showing water flows through the pipe contractions. The
relation between discharges Q1 in figure (1) and Q2 in figure (2) would be best
expressed by:
a) Q1 > Q2 b) Q1 < Q2 c) Q1 = Q2 d) No relation
0.2 m 0.2 m
D
Q1 0.1 m Q2
D
0.1 m
Fig (4) Fig (5)
2
1) Due to gravity, the velocity at (b) as compared to that at (a) in figure (1) must be:
a) smaller b) larger c) equal
a
Q=Constant
b
Fig (1)
2) Due to gravity, the pressure at (b) as compared to that at (a) in figure (1) must be:
a) smaller b) larger c) equal
3) If the fluid in the pipe shown in figure (1) is compressible (ρ ∞ pressure) then
the velocity at (b) as compared to that at (a) must be:
a) smaller b) larger c) equal
4) A tank has a water level of 25.0 m above a random datum feeds a pipeline AB
ending at B with an outlet of 4.0 cm diameter. T h e p i p e AB h as a di a m et e r
o f 15.0 cm with point A 20.0 m above the datum and point B at the datum. Find:
a) The discharge through the pipeline and the pressures and water velocities at A & B.
b) If friction losses in the nozzle are 0.5 m, and between A & B are 5.0 m, solve
(a) and plot the hydraulic gradient line and total energy line.
5) Relative to the Total Energy Line, the Hydraulic Gradient Line may not fall:
a) above b) coincide c) below
6) For any orifice, which of the following statements is
correct: a) Cv ≥ 1.0 b) Cv > 1.0 c) Cv <
1.0 d) Cv ≤ 1.0
7) Water issues from a 10.0 cm diameter circular sharp edged orifice under a head of
12.0 m. If a volume of 13.6 m3 is collected in 3 minutes, and the diameter of the jet
at the venacontracta is 8.0 cm, then the values for Cd , Cv & Cc are:
a) 0.64, 0.8 and 0.8 b) 0.63, 0.64 and 0.98 c) 0.51, 0.8 and 0.64
8) Water flows steadily (assumed ideal fluid) from a large b
tank and exits through a constant diameter vertical pipe Fig
as shown in Fig. (2). The air in the tank is pressurized (2) 50
to 50 kN/m2. The height (h) to which water rises is: KN/m2
h
a) 3.1 m b) 7.1 m c) 50 m d) 35 m Air
Water
9) The water velocity in the vertical pipe in figure (2) is:
2m
a) 30.7 m/s b) 7.8 m/s c) 4.6 m/s d) 2.1 m/s
1
, 10) In figure (2), pressure at (a) as compared to pressure at (b) is:
a) smaller b) larger c) equal
11) The velocity of water in a pipe of 10.0 cm diameter is 3.0 m/s. The nozzle at the
end of the pipe has a velocity coefficient of 0.98. If the pressure in the pipe is
0.7 kg/cm2, find the jet diameter, the rate of flow, and the power lost due to
friction in the nozzle.
12) A 5.0-cm diameter orifice (Cd = 0.6) discharges water
from tank A to tank B as shown in fig (3). The reading in the Air Fig (3)
vacuum gauge in tank B is 0.65 Kg/cm2 below atmospheric 2m Oil
- 0.65
pressure, and the air pressure (0.8)
Kg/cm2
above the oil in tank A is 70 KN/m2 , find the discharge from the
orifice and the distance (L). Water
2m
5m 1m
13) In figure (3), if the vacuum gauge reads 0.3 Kg/cm2 instead of L
0.65 Kg/cm2, the pressure change would cause the discharge
through the orifice to:
a) Increase b) decrease c) remain the same
14) A convergent-divergent nozzle is fitted to the side of a water tank, which discharges
7.0 lit/s to the atmosphere where the head on the nozzle is 1.8 m. The exit has a diameter of
4.06 cm, the water vapor pressure is 0.5 m absolute and the height of water in the
barometer is 10.33 m. Neglecting the losses in the convergent part of the nozzle, the
coefficient of discharge Cd and the minimum diameter at the throat of the nozzle Dmin would
be:
a) Cd= 0.91 Dmin=2.53cm b) Cd= 0.81 Dmin=2.53cm c) Cd= 0.91 Dmin=2.43cm
15) Figures (4) and (5) are showing water flows through the pipe contractions. The
relation between discharges Q1 in figure (1) and Q2 in figure (2) would be best
expressed by:
a) Q1 > Q2 b) Q1 < Q2 c) Q1 = Q2 d) No relation
0.2 m 0.2 m
D
Q1 0.1 m Q2
D
0.1 m
Fig (4) Fig (5)
2
