Introduction to Fluid Mechanics

738 Pages·2010·13.91 MB·English

by  William S. Janna

Introduction to
Fluid
Mechanics
FOURTH EDITION
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Introduction to
Fluid
Mechanics
FOURTH EDITION
William S. Janna
University of Memphis
Memphis, Tennessee, U.S.A.
Boca Raton London New York
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Library of Congress Cataloging-in-Publication Data
Janna, William S.
Introduction to fluid mechanics / William S. Janna. -- 4th ed.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-4200-8524-2 (hardcover : alk. paper)
1. Fluid mechanics. I. Title.
TA357.J36 2010
620.1’06--dc22 2009026753
Visit the Taylor & Francis Web site at
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Dedication
To Him who ordered the Universe by a word;
Whose love and glory are seen in the
beauty of natural science and in
the accomplishments of simple men;
And to my lovely wife Marla, who daily reflects
this love and glory to me.
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Contents
Preface............................................................................................................................................xiii
Acknowledgments...........................................................................................................................xv
Introduction toFluid Mechanics...................................................................................................xvii
Author............................................................................................................................................xix
Chapter 1 Fundamental Concepts................................................................................................1
1.1 Definitionof a Fluid..............................................................................................................1
1.2 Dimensions and Units............................................................................................................2
1.3 Properties ofFluids................................................................................................................7
1.3.1 Viscosity...................................................................................................................7
1.3.1.1 Time-Independent Fluids............................................................................9
1.3.1.2 Time-Dependent Fluids...............................................................................9
1.3.1.3 ViscoelasticFluids......................................................................................9
1.3.2 Pressure...................................................................................................................12
1.3.3 Density....................................................................................................................12
1.3.4 Kinematic Viscosity................................................................................................13
1.3.5 Surface Tension......................................................................................................13
1.3.6 Specific Heat...........................................................................................................16
1.3.7 Internal Energy........................................................................................................18
1.3.8 Enthalpy..................................................................................................................19
1.3.9 Compressibility Factor=Bulk Modulus...................................................................19
1.3.10 Ideal Gas Law.........................................................................................................21
1.4 Liquids and Gases................................................................................................................22
1.5 Continuum............................................................................................................................22
Problems..........................................................................................................................................23
Chapter 2 Fluid Statics...............................................................................................................35
2.1 Pressure and PressureMeasurement....................................................................................35
2.2 Hydrostatic Forces onSubmerged Plane Surfaces..............................................................47
2.3 Hydrostatic Forces onSubmerged Curved Surfaces...........................................................55
2.4 Equilibriumof AcceleratingFluids.....................................................................................61
2.5 Forces on Submerged Bodies..............................................................................................67
2.6 Stability of Submergedand FloatingBodies.......................................................................71
2.7 Summary..............................................................................................................................75
Problems..........................................................................................................................................76
Chapter 3 Basic Equationsof Fluid Mechanics.......................................................................101
3.1 Kinematics ofFlow............................................................................................................101
3.2 Control Volume Approach.................................................................................................103
3.3 Continuity Equation...........................................................................................................107
3.4 Momentum Equation.........................................................................................................112
3.4.1 Linear Momentum Equation.................................................................................113
3.4.2 Angular Momentum Equation..............................................................................117
vii
viii Contents
3.5 Energy Equation...............................................................................................................120
3.6 Bernoulli’sEquation........................................................................................................126
3.7 Summary..........................................................................................................................135
Problems........................................................................................................................................135
Chapter 4 Dimensional Analysisand Dynamic Similitude.....................................................155
4.1 Dimensional Homogeneity and Analysis........................................................................155
4.1.1 RayleighMethod...................................................................................................157
4.1.2 BuckinghamPi Method........................................................................................161
4.2 Dimensionless Ratios.......................................................................................................163
4.2.1 Flow ina Pipe orConduit....................................................................................163
4.2.2 Flow over ImmersedBodies.................................................................................164
4.2.3 Open-Channel Flow..............................................................................................164
4.2.4 Unbounded Flows.................................................................................................165
4.3 Dimensional Analysisby Inspection...............................................................................165
4.4 Similitude.........................................................................................................................167
4.4.1 Geometric Similarity.............................................................................................168
4.4.2 DynamicSimilarity...............................................................................................169
4.4.3 Modeling...............................................................................................................171
4.5 Correlation ofExperimentalData....................................................................................175
4.6 Summary..........................................................................................................................180
Problems........................................................................................................................................180
Chapter 5 Flow in Closed Conduits.........................................................................................193
5.1 Laminarand TurbulentFlow...........................................................................................193
5.2 Effect of Viscosity...........................................................................................................196
5.2.1 Entrance Effects....................................................................................................197
5.3 PipeDimensions andSpecifications................................................................................199
5.3.1 EquivalentDiametersfor NoncircularDucts........................................................201
5.4 Equationof Motion..........................................................................................................203
5.5 The Friction Factor and Pipe Roughness........................................................................206
5.5.1 Flow throughPipes ofNoncircular Cross Sections..............................................211
5.5.2 Flow throughan Annulus.....................................................................................213
5.5.3 Miscellaneous Geometries....................................................................................216
5.6 Simple Piping Systems....................................................................................................216
5.7 Minor Losses....................................................................................................................227
5.8 Forces Exerted on Fittings byMoving Fluids.................................................................240
5.9 Pipes in Parallel...............................................................................................................243
5.10 Pumps and PipingSystems..............................................................................................247
5.11 Summary..........................................................................................................................250
Problems........................................................................................................................................251
Chapter 6 Flow over Immersed Bodies...................................................................................269
6.1 Boundary-Layer Growthand Separation.........................................................................269
6.1.1 Boundary-Layer Growth.......................................................................................269
6.1.2 Separation..............................................................................................................275
6.2 Drag on Various Two-DimensionalBodies....................................................................276
6.3 Drag on Various Three-Dimensional Bodies..................................................................283
Contents ix
6.4 Applications toGroundVehicles.....................................................................................287
6.4.1 Bicycle–Rider Combinations................................................................................288
6.4.2 Automobiles..........................................................................................................293
6.4.3 Tractor-Trailer Trucks...........................................................................................293
6.5 Lift on Airfoils.................................................................................................................298
6.6 Summary..........................................................................................................................305
Problems........................................................................................................................................305
Chapter 7 Flow in Open Channels...........................................................................................325
7.1 Types ofOpen-Channel Flows........................................................................................325
7.2 Open-Channel Geometry Factors....................................................................................326
7.3 Energy Considerations inOpen-Channel Flows..............................................................329
7.3.1 Flow under aSluice Gate.....................................................................................329
7.3.2 Flow througha Venturi Flume.............................................................................331
7.4 Critical Flow Calculations...............................................................................................335
7.5 Equationsfor Uniform Open-Channel Flows..................................................................338
7.5.1 LaminarOpen-Channel Flow...............................................................................338
7.5.2 Reynolds NumberandTransition.........................................................................341
7.5.3 TurbulentOpen-Channel Flow.............................................................................342
7.6 Hydraulically Optimum Cross Section............................................................................348
7.7 Nonuniform Open-Channel Flow....................................................................................351
7.7.1 GraduallyVariedFlow.........................................................................................351
7.7.2 RapidlyVariedFlow.............................................................................................361
7.8 Summary..........................................................................................................................367
Problems........................................................................................................................................367
Chapter 8 Compressible Flow..................................................................................................377
8.1 Sonic Velocity and Mach Number..................................................................................378
8.2 Stagnation Properties and IsentropicFlow......................................................................382
8.3 Flow througha Channelof Varying Area.......................................................................386
8.4 Normal ShockWaves......................................................................................................397
8.5 Compressible Flow with Friction....................................................................................404
8.6 Compressible Flow with Heat Transfer...........................................................................409
8.7 Summary..........................................................................................................................416
Problems........................................................................................................................................416
Chapter 9 Turbomachinery......................................................................................................423
9.1 Equationsof Turbomachinery..........................................................................................424
9.2 Axial-Flow Turbines........................................................................................................430
9.3 Axial-Flow Compressors, Pumps, andFans....................................................................453
9.4 Radial-Flow Turbines......................................................................................................466
9.5 Radial-Flow Compressors and Pumps.............................................................................470
9.6 Power-Absorbing versus Power-Producing Machines....................................................476
9.7 Dimensional Analysisof Turbomachinery......................................................................478
9.8 Performance Characteristics ofCentrifugal Pumps.........................................................479
9.9 Performance Characteristics ofHydraulic Turbines........................................................487
9.10 Summary..........................................................................................................................488
Problems........................................................................................................................................489