Problem set 3
1. Consider water in a container and air in a tornado flow in horizontal circular streamlines of
radius r and speed V as shown in Figure 3-1. Determine the radial pressure gradient, dp/dr,
needed for the following situations:
(a) The fluid is water with r = 3 in and V = 0.8 ft/s. (4.97 lbf/ft3)
(b) The fluid is air with r = 300 ft and V = 200 mph. (0.681 lbf/ft3)
Figure 3-1 Horizontal circular streamline.
2. Water flowing from the 0.75-in.-diameter outlet shown in Figure 3-2 rises 2.8 inches above
the outlet. Determine the flowrate. (0.0119 ft3/s)
Figure 3-2 Water flowing from an outlet
3. When an airplane is flying 200 mph at 5000-ft altitude (assume the air density is 2.048 × 10-3
slug/ft3) in a standard atmosphere, the air velocity at a certain point on the wing is 273 mph
relative to the airplane.
(a) What suction pressure is developed on the wing at that point? ( 76 lbf/ft2)
(b) What is the pressure at the leading edge (a stagnation point) of the wing? (88 lbf/ft2)
4. A loon is a diving bird equally at home “flying” in the air or water. What swimming velocity
under water will produce a dynamic pressure equal to that when it flies in the air at 40 mph?
(1.40 mph)
5. A 0.15-m-diameter pipe (a) discharges into a 0.1-m-diameter pipe (b). Determine the velocity
head in each pipe if they are carrying 0.14 m3/s of kerosene.
(a) 3.199
(b) 16.195 m
6. A smooth plastic, 10-m-long garden hose with an inside diameter of 20 mm is used to drain a
wading pool as is shown in Figure 3-6. If viscous effects are neglected, what is the flowrate from
the pool? (9.11×10-4 m3/s)
((9.11
Figure 3-6 Long garden hose.
7. Water flows steadily from the large open tank shown in Figure 3-7. If viscous effects are
negligible, determine (a) the flow rate Q, and (b) the manometer reading h.
(a) 0.0696
m3/s
Figure 3-7 Water flows from open tank.
(b) 0.574 m
8. Water is siphoned from the tank shown in Figure 3-8. Determine the flowrate from the tank
and the pressures at points (1), (2), and (3) if viscous effects are negligible.
0.141 ft3/s, (1) 499 lbf/ft2, (2) 312 lbf/ft2, (3) 312 lbf/ft2
Figure 3-8 Water siphoned from a tank.
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