Chapter 7
Energy Principle
Problem 7.1
Air ows through a rectangular duct of dimension 1 ft 5 ft. The velocity prole
is linear, with a maximum velocity of 15 ft/s. Find the kinetic energy correction
factor.
Solution
The kinetic energy correction factor is
Chapter 10
Flow in Conduits
Problem 10.1
Water at 20o C ( = 10 3 Ns/m2 , = 1000 kg/m3 ) ows through a 0.5-mm tube
connected to the bottom of a reservoir. The length of the tube is 1.0 m, and the
depth of water in the reservoir is 20 cm. Find the ow rate i
Chapter 2
Fluid Properties
Problem 2.1
Calculate the density and specic weight of nitrogen at an absolute pressure of
1 MPa and a temperature of 40r C.
Solution
Ideal gas law
=
s
UW
From Table A.2, U = 297 J/kg/K. The temperature in absolute units is W =
Chapter 1
Introduction
Problem 1.1
Consider a glass container, half-full of water and half-full of air, at rest on a laboratory table. List some similarities and dierences between the liquid (water) and
the gas (air).
Solution
Similarities
1. The gas and
Chapter 9
Surface Resistance
Problem 9.1
An aluminum cube of density 2700 kg/m3 slides with a constant speed of 20 cm/s
down a plate that is at an angle of 30r with respect to the horizontal. The plate is
covered with a stationary layer of 0.1-mm-thick oi
Chapter 8
Dimensional Analysis and
Similitude
Problem 8.1
The discharge, T> of an ideal uid (no viscous eects) through an orice depends
on the orice diameter, g, the pressure drop across the orice, s, and the uid
density. Find a nondimensional relationshi
Chapter 15
Varied Flow in Open
Channels
Problem 15.1
Water ows in a circular concrete pipe (Mannings q = 0=012) with a depth that is
half of the pipe diameter (0.8 m). If the slope is 0.004, nd the ow rate.
Solution
The ow rate is obtained from the Chezy
Chapter 6
Momentum Principle
Problem 6.1
Water at 20o C is discharged from a nozzle onto a plate as shown. The ow rate of
the water is 0.001 m3 @s, and the diameter of the nozzle outlet is 0.5 cm. Find the
force necessary to hold the plate in place.
Solut
Chapter 14
Turbomachinery
Problem 14.1
A propeller is to be selected for a light airplane with a mass of 1500 kg which
will cruise at 100 m/s at an altitude where the density is 1 kg/m3 The lift-to-drag
ratio at cruise conditions is 30:1, and the engine r
Chapter 5
Control Volume Approach
and Continuity Principle
Problem 5.1
A 10-cm-diameter pipe contains sea water that ows with a mean velocity of 5
m/s. Find the volume ow rate (discharge) and the mass ow rate.
Solution
The discharge is
T=YD
where Y is the
Chapter 4
Flowing Fluids and Pressure
Variation
Problem 4.1
A ow moves in the cfw_-direction with a velocity of 10 m/s from 0 to 0.1 second
and then reverses direction with the same speed from 0.1 to 0.2 second. Sketch
the pathline starting from cfw_ = 0
Chapter 13
Flow Measurements
Problem 13.1
Velocity in an air ow is to be measured with a stagnation tube that has a resolution of 0.1-in. H2 O. Find the minimum uid speed in ft/s that can be measured.
Neglect viscous eects and assume that the air is at ro
Chapter 12
Compressible Flow
Problem 12.1
Methane at 25o C (U = 518 J/kg/K, n = 1=31) is owing in a pipe at 400 m/s.
Is the ow subsonic, sonic, supersonic, or hypersonic?
Solution
The speed of sound in methane is
s
s
f = nUW = 1=31 518 298
= 450 m/s
Becau
Chapter 3
Fluid Statics
Problem 3.1
For a lake, nd the depth k at which the gage pressure is 1 atmosphere.
specic weight of water is 62.3 lbf/ft3 .
The
Solution
At the free surface of the lake, pressure will be ssurface = 1=0 atm absolute or 0.0
atm gage.
Chapter 11
Drag and Lift
Problem 11.1
Air with a speed of Yr ows over a long bar that has a 15r wedge-shaped crosssection. The pressure variation, as represented using the coe!cient of pressure, is
shown in the following sketch. On the west face of the ba