Page 198 - Water Engineering Hydraulics, Distribution and Treatment

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5.30
A
has a specific gravity of 1.03. Determine the iceberg’s percentage
B
volume exposed in air when it is floating in seawater.
D
D
1
2
5.31
A vertical sliding gate 25 ft (7.62 m) wide and 35 ft
(10.668 m) high is submerged in 45 ft (13.76 m) of water. It has a
Figure 5.43 Conical reducer connecting two pipes.
coefficient of friction equals 0.2 between its guides and its edges.
The gate weighs 6.5 tons (13,000 lb = 5,902 kg). Assume friction
is due to the normal force of water pressure on the gate and neglect
end restraint from the pipes. Determine the tensile force in lb (kN),
the buoyant force of the water. Determine the vertical force that is
which is exerted on the connecting reducer joint.
required to just lift the gate. The following values for the distances
in Fig. 5.46 are a = 10 ft (3.048 m); b = 27.5 ft (8.382 m); c = 45 ft
(13.716 m); and h = 35 ft (10.668 m).
A rectangular access port 2 ft by 2 ft (0.6096 m by 0.6096 m)
5.27 Chapter 5 Water Hydraulics, Transmission, and Appurtenances Ice in an iceberg has a specific gravity of 0.91. Seawater
in size, shown in Fig. 5.44, seals an environmental test chamber that
2
is pressurized to 16 psi (111.04 kPa = 111.04 kN/m ) above external Water surface
pressure. What force in lb (kN) does the port exert upon its retaining
P f
structure? a
b
c
P avg C g h
Weight
Exterior H Pressure chamber
Figure 5.46 Vertical force to lift a sliding gate.
5.32 A cylinder of cork is floating upright in a container partially
filled with water. A vacuum is applied to the container such that the
air within the vessel is partially removed. The cork will
1. Rise somewhat in the water
Figure 5.44 Access port of a pressure chamber.
2. Sink somewhat in the water
3. Remain stationary
5.28 Commercial chemical liquid stored in an above-ground 4. Turn over on its side
◦
◦
spherical steel tank at 102 F (38.89 C) generates a gauge pressure 5. Sink to the bottom of the container
2
of 80 psig (555.2 kPa = 555.2 kN/m ). If the chemical storage tank Select the correct answer and explain why.
is 6 ft (1.829 m) in diameter and has walls 0.25 in. (6.35 mm) thick,
2
determine the maximum tensile stress in psi (kN/m ) developed in
3
3
5.33 An incompressible fluid ( = 52 lb/ft = 8.175 kN/m )enters
the steel.
and leaves a hydraulic system with the following energy in ft-lb/lb
(m-kg/kg) of fluid:
5.29 A steel-reinforced fiber glass cylinder butane storage tank
1. Potential energy z above datum:
16 ft (4.88 m) long shown in Fig. 5.45 has hemispherically domed
ends 6 ft (1.829 m) in diameter. Butane has a vapor pressure of
◦
◦
2
46 psig (319.24 kN/m = 319.24 kPa) at 102 F (38.89 C) and the Entering = 6ft = 1.8288 m.
tank walls are 0.25 in. (6.35 mm) thick. Determine the maximum Leaving = 16 ft = 4.8768 m.
2
2
tensile stress in lb/in (kN/m ) developed in the tank.
2
2. Kinetic energy, v ∕2g:
Entering = 6ft = 1.8288 m.
Leaving = 11 ft = 3.3528 m.
D
3. Pressure energy, P/ :
L
Entering = 32 ft = 9.7536 m.
Figure 5.45 Cylindrical liquid storage with hemispherical domed
ends. Leaving = 152 ft = 46.3296 m.