The University of Sydney
School of Aerospace, Mechanical and Mechatronic Engineering
AMME2200 THERMOFLUIDS
Fluid Mechanics
Assignment 1
Due: 5pm, Friday September 9, 2011
This assignment should require around 9 hours of work by an average student.
Place completed assignment in the box marked AMME2200 on level 3 (outside Room 339) in the
Mechanical Engineering building.
Assignment Problems:
1. The velocity distribution in a 1.0 cm diameter pipe is given by u(r)=16(1 - r2/ro2) m/s, where ro is
the pipe radius. Calculate the shear stress at the centerline, at r=0.25 cm and at the wall if water at 20oC is
flowing. (Ans. 0, 3.2 Pa, 6.4 Pa)
2. A 2 mm diameter bubble is formed by a stream of 10oC water. Determine the gauge pressure in the
bubble. Surface tension data: see text, P 448. (Ans. 299 Pa)
3. A 2 m wide, 3 m high vertical rectangular gate has its top edge 2 m below the water level. It is hinged
along its lower edge. What horizontal force, acting on the top edge, is needed to hold the gate shut? ( Ans.
88.3 kN)
4. A turbine which is 87% efficient accepts 2 m3/s of water from a 50 cm diameter pipe. The pressure drop
is 600 kPa and the exit velocity is small. Determine the turbine output. (Ans. 1.135 MW)
5.The exit area of the nozzle in a fireman’s hose is so small that the velocity in the hose is negligible.
What is the maximum exit velocity and the maximum height the water can reach if the pressure in the hose
is 700 kPa? (Ans. 37.4 m/s, 71.4 m)
6. A pitot-static tube is used to measure the velocity of an aircraft flying at 1000 m (see Table A24).
Calculate the velocity for a pressure reading of 2 kPa.. (Ans. 59.9 m/s)
7. A 75% efficient pump delivers 0.1 m3 of water from a reservoir to a device at an elevation of 50 m
above the reservoir. The pressure at the 8-cm diameter entrance to the device is 180 kPa. The piping loss
coefficient is 5.6. Determine the pump input power needed. (Ans. 264 kW)
8. Water flows at the rate of 600 l/min in a 4 cm diameter horizontal pipe with a pressure of 690 kPa. If
the pressure after an enlargement to 6 cm diameter is measured to be 700 kPa, calculate the head loss across
the enlargement. (Ans. 1.57 m)
Tutorial set 1: see overleaf
Tutorial set 1 (not to be handed in): (From Masri; Thermodynamics and Fluids, 2010 )
These questions are exercises only. Completing some or all of these will assist you greatly in solving the
assignment questions.
Answer
Answer
10-22
0.55 Nm
11-30
1053 kg/m3
2
10-26
0.0231 Ns/m
10-28
0.565N
11-32
2987kg/m3
10-36
0.0232 N/m
11-33
10-37
100 Pa, 4 Pa
11-58
10-39
0.075 N/m
11-59
10-40
2.4 mm, 4.1 mm
11-64
11-73
9.5 cm, 59.7 N
12-6
77.6%, 72.7%

12-7
2121 kW, 636 kW
10-49
0.79 Nm, 0.063 Nm
12-10
67.2 % , 196 kPa
12-25
334 kPa
11-8
83.0 kN, 8.56 m
12-27
11-12
12-34a
hmax = 1/(2g)*{4min/(Do2)}2
11-13
9.134*107 N
12-41
6.24 cm
11-14
288 kN
12-44
0.15 m/s
11-21
0.38 m, 0.52 m
12-45
12-46
33.8 m/s
12-55
7.14*10-3 m3/s, 299 kpa
11-23
177 kN
12-56
6.12*10-3 m3/s
12-66
$68,900/year
12-76
12-79
12-82
31.2 kPa