fluid_mechanics

Problems 257
300 mm
5.99 A siphon is used to draw water at 20°C from a large container
as indicated in Fig. P5.99. Does changing the elevation, h, of the
siphon centerline above the water level in the tank vary the flowrate
through the siphon? Explain. What is the maximum allowable
value of h?
0.6 m
25
mm
h
h
100 mm
F I G U R E P5.95
1 m
0.75 m
1.5 m
1.0 m
6 m
3 m
F I G U R E P5.99
5.100 A water siphon having a constant inside diameter of 3 in. is
arranged as shown in Fig. P5.100. If the friction loss between A and
B is 0.8V 2 2, where V is the velocity of flow in the siphon, determine
the flowrate involved.
F I G U R E P5.96
5.97 Water flows through a vertical pipe, as is indicated in
Fig. P5.97. Is the flow up or down in the pipe? Explain.
A
4 ft
4 ft
12 ft
H
3 in.
B
F I G U R E P5.100
Mercury
F I G U R E P5.97
h
5.101 Water flows through a valve (see Fig.P5.101) at the rate of
1000 lbm/s. The pressure just upstream of the valve is 90 psi and the
pressure drop across the valve is 50 psi. The inside diameters of
the valve inlet and exit pipes are 12 and 24 in. If the flow through
the valve occurs in a horizontal plane determine the loss in available
energy across the valve.
5.98 A circular disk can be lifted up by blowing on it with the device
shown in Fig. P5.98. Explain why this happens.
Flow
12 in.
Tube
Disk
attached
to tube
F I G U R E P5.98
Flow
Disk
to be
lifted
24 in.
F I G U R E P5.101
5.102 Compare the volume flowrates associated with two different
vent configurations, a cylindrical hole in the wall having a diameter
of 4 in. and the same diameter cylindrical hole in the wall