FUNDAMENTALS OF FLUID MECHANICSPDF电子书下载

1INTRODUCTION 3

1.1 Some Characteristics of Fluids 4

1.2 Dimensions，Dimensional Homogeneity，and Units 5

1.2.1 Systems of Units 8

1.3 Analysis of Fluid Behavior 13

1.4 Measures of Fluid Mass and Weight 13

1.4.1 Density 13

1.4.2 Specific Weight 15

1.4.3 Specific Gravity 15

1.5 Ideal Gas Law 15

1.6 Viscosity 18

1.7 Compressibility of Fluids 24

1.7.1 Bulk Modulus 24

1.7.2 Compression and Expansion of Gases 25

1.7.3 Speed of Sound 26

1.8 Vapor Pressure 28

1.9 Surface Tension 28

1.10 A Brief Look Back in History 31

References 33

Problems 34

2FLUID STATI CS 41

2.1 Pressure at a Point 41

2.2 Basic Equation for Pressure Field 42

2.3 Pressure Variation in a Fluid at Rest 44

2.3.1 Incompressible Fluid 45

2.3.2 Compressible Fluid 48

2.4 Standard Atmosphere 50

2.5 Measurement of Pressure 51

2.6 Manometry 53

2.6.1 Piezometer Tube 53

2.6.2 U-Tube Manometer 54

2.6.3 Inclined-Tube Manometer 58

2.7 Mechanical and Electronic Pressure Measuring Devices 58

2.8 Hydrostatic Force on a Plane Surface 61

2.9 Pressure Prism 67

2.10 Hydrostatic Force on a Curved Surface 71

2.11 Buoyancy，Flotation，and Stability 74

2.11.1 Archimedes’ Principle 74

2.11.2 Stability 76

2.12 Pressure Variation in a Fluid with Rigid-Body Motion 78

2.12.1 Linear Motion 78

2.12.2 Rigid-Body Rotation 81

References 84

Problems 84

3ELEMENTARY FLUID DYNAMICS—THE BERNOULLI EQUATION 101

3.1 Newton’s Second Law 101

3.2 F = ma Along a Streamline 104

3.3 F = ma Normal to a Streamline 109

3.4 Physical Interpretation 112

3.5 Static，Stagnation，Dynamic，and Total Pressure 115

3.6 Examples of Use of the Bernoulli Equation 119

3.6.1 Free Jets 120

3.6.2 Confined Flows 122

3.6.3 Flowrate Measurement 130

3.7 The Energy Line and the Hydraulic Grade Line 135

3.8 Restrictions on the Use of the Bernoulli Equation 138

3.8.1 Compressibility Effects 138

3.8.2 Unsteady Effects 141

3.8.3 Rotational Effects 145

3.8.4 Other Restrictions 146

References 147

Problems 147

4FLUID KINEMATICS 165

4.1 The Velocity Field 165

4.1.1 Eulerain and Lagrangian Flow Descriptions 166

4.1.2 One-，Two-，and Three-Dimensional Flows 169

4.1.3 Steady and Unsteady Flows 170

4.1.4 Streamlines，Streaklines，and Pathlines 171

4.2 The Acceleration Field 175

4.2.1 The Material Derivative 176

4.2.2 Unsteady Effects 179

4.2.3 Convective Effects 180

4.2.4 Streamline Coordinates 183

4.3 Control Volume and System Representation 185

4.4 The Reynolds Transport Theorem 186

4.4.1 Derivation of the Reynolds Transport Theorem 189

4.4.2 Physical Interpretation 194

4.4.3 Relationship to Material Derivative 197

4.4.4 Steady Effects 197

4.4.5 Unsteady Effects 198

4.4.6 Moving Control Volumes 199

4.4.7 Selection of a Control Volume 201

References 202

Problems 202

5FINITE CONTROL VOLUME ANALYSIS 211

5.1 Conservation of Mass—The Continuity Equation 212

5.1.1 Derivation of the Continuity Equation 212

5.1.2 Fixed，Nondeforming Control Volume 214

5.1.3 Moving，Nondeforming Control Volume 221

5.1.4 Deforming Control Volume 224

5.2 Newton’s Second Law—The Linear Momentum and Moment-of-Momentum Equations 227

5.2.1 Derivation of the Linear Momentum Equation 227

5.2.2 Application of the Linear Momentum Equation 229

5.2.3 Derivation of the Moment-of-Momentum Equation 246

5.2.4 Application of the Moment-of-Momentum Equation 248

5.3 First Law of Thermodynamics—The Energy Equation 257

5.3.1 Derivation of the Energy Equation 257

5.3.2 Application of the Energy Equation 260

5.3.3 Comparison of the Energy Equation with the Bernoulli Equation 265

5.3.4 Application of the Energy Equation to Nonuniform Flows 272

5.3.5 Combination of the Energy Equation and the Moment-of-Momentum Equation 277

5.4 Second Law of Thermodynamics—Irreversible Flow 278

5.4.1 Semi-infinitesimal Control Volume Statement of the Energy Equation 278

5.4.2 Semi-infinitesimal Control Volume Statement of the Second Law of Thermodynamics 279

5.4.3 Combination of the Equations of the First and Second Laws of Thermodynamics 280

5.4.4 Application of the Loss Form of the Energy Equation 281

References 283

Problems 283

6DIFFERENTIAL ANALYSIS OF FLUID FLOW 309

6.1 Fluid Element Kinematics 310

6.1.1 Velocity and Acceleration Fields Revisited 310

6.1.2 Linear Motion and Deformation 311

6.1.3 Angular Motion and Deformation 313

6.2 Conservation of Mass 316

6.2.1 Differential Form of Continuity Equation 316

6.2.2 Cylindrical Polar Coordinates 319

6.2.3 The Stream Function 320

6.3 Conservation of Linear Momentum 323

6.3.1 Description of Forces Acting on Differential Element 324

6.3.2 Equations of Motion 326

6.4 Inviscid Flow 327

6.4.1 Euler’s Equations of Motion 327

6.4.2 The Bernoulli Equation 328

6.4.3 Irrotational Flow 330

6.4.4 The Bernoulli Equation for Irrotational Flow 332

6.4.5 The Velocity Potential 332

6.5 Some Basic，Plane Potential Flows 337

6.5.1 Uniform Flow 338

6.5.2 Source and Sink 339

6.5.3 Vortex 341

6.5.4 Doublet 344

6.6 Superposition of Basic，Plane Potential Flows 346

6.6.1 Source in a Uniform Stream—Half-Body 347

6.6.2 Rankine Ovals 350

6.6.3 Flow Around a Circular Cylinder 352

6.7 Other Aspects of Potential Flow Analysis 358

6.8 Viscous Flow 359

6.8.1 Stress-Deformation Relationships 359

6.8.2 The Naiver-Stokes Equations 360

6.9 Some Simple Solutions for Viscous，Incompressible Fluids 362

6.9.1 Steady，Laminar Flow Between Fixed Parallel Plates 362

6.9.2 Couette Flow 365

6.9.3 Steady，Laminar Flow in Circular Tubes 367

6.9.4 Steady，Axial，Laminar Flow in an Annulus 370

6.10 Other Aspects of Differential Analysis 372

6.10.1 Numerical Methods 373

References 381

Problems 382

7SIMILITUDE，DIMENSIONAL ANALYSIS，AND MODELING 395

7.1 Dimensional Analysis 395

7.2 Buckingham Pi Theorem 398

7.3 Determination of Pi Terms 398

7.4 Some Additional Comments About Dimensional Analysis 405

7.4.1 Selection of Variables 405

7.4.2 Determination of Reference Dimensions 407

7.4.3 Uniqueness of Pi Terms 409

7.5 Determination of Pi Terms by Inspection 410

7.6 Common Dimensionless Groups in Fluid Mechanics 412

7.7 Correlation of Experimental Data 416

7.7.1 Problems with One Pi Term 416

7.7.2 Problems with Two or More Pi Terms 418

7.8 Modeling and Similitude 421

7.8.1 Theory of Models 421

7.8.2 Model Scales 426

7.8.3 Practical Aspects of Using Models 426

7.9 Some Typical Model Studies 428

7.9.1 Flow Through Closed Conduits 428

7.9.2 Flow Around Immersed Bodies 431

7.9.3 Flow with a Free Surface 435

7.10 Similitude Based on Governing Differential Equations 439

References 442

Problems 442

8VISCOUS FLOW IN PIPES 455

8.1 General Characteristics of Pipe Flow 456

8.1.1 Laminar or Turbulent Flow 457

8.1.2 Entrance Region and Fully Developed Flow 459

8.1.3 Pressure and Shear Stress 460

8.2 Fully Developed Laminar Flow 462

8.2.1 From F = ma Applied to a Fluid Element 462

8.2.2 From the Navier-Stokes Equations 467

8.2.3 From Dimensional Analysis 469

8.2.4 Energy Considerations 470

8.3 Fully Developed Turbulent Flow 473

8.3.1 Transition from Laminar to Turbulent Flow 473

8.3.2 Turbulent Shear Stress 475

8.3.3 Turbulent Velocity Profile 480

8.4 Dimensional Analysis of Pipe Flow 484

8.4.1 The Moody Chart 484

8.4.2 Minor Losses 492

8.4.3 Noncircular Conduits 504

8.5 Pipe Flow Examples 508

8.5.1 Single Pipes 508

8.5.2 Multiple Pipe Systems 520

8.6 Pipe Flowrate Measurement 526

8.6.1 Pipe Flowrate Meters 526

8.6.2 Volume Flow Meters 531

References 533

Problems 534

9FLOW OVER IMMERSED BODIES 549

9.1 General External Flow Characteristics 550

9.1.1 Life and Drag Concepts 552

9.1.2 Characteristics of Flow Past an Object 555

9.2 Boundary Layer Characteristics 560

9.2.1 Boundary Layer Structure and Thickness on a Flat Plate 560

9.2.2 Prandtl/Blasius Boundary Layer Solution 564

9.2.3 Momentum Integral BoundaryLayer Equation for a Flat Plate 568

9.2.4 Transition from Laminar to Turbulent Flow 575

9.2.5 Turbulent Boundary Layer Flow 577

9.2.6 Effects of Pressure Gradient 583

9.2.7 Momentum Integral Boundary Layer Equation with Nonzero Pressure Gradient 588

9.3 Drag 589

9.3.1 Friction Drag 589

9.3.2 Pressure Drag 591

9.3.3 Drag Coefficient Data and Examples 594

9.4 Lift 611

9.4.1 Surface Pressure Distribution 611

9.4.2 Circulation 622

References 626

Problems 627

10OPEN-CHANNEL FLOW 639

10.1 General Characteristics of Open-Channel Flow 640

10.2 Surface Waves 641

10.2.1 Wave Speed 641

10.2.2 Froude Number Effects 644

10.3 Energy Considerations 645

10.3.1 Specific Energy 646

10.3.2 Channel Depth Variations 651

10.4 Uniform Depth Channel Flow 652

10.4.1 Uniform Flow Approximations 652

10.4.2 The Chezy and Manning Equations 653

10.4.3 Uniform Depth Examples 656

10.5 Gradually Varied Flow 665

10.5.1 Classification of Surface Shapes 666

10.5.2 Examples of Gradually Varied Flows 667

10.6 Rapidly Varied Flow 669

10.6.1 The Hydraulic Jump 670

10.6.2 Sharp-Crested Weirs 676

10.6.3 Broad-Crested Weirs 680

10.6.4 Underflow Gates 683

References 686

Problems 686

11COMPRESSIBLE FLOW 697

11.1 Ideal Gas Relationships 698

11.2 Mach Number and Speed of Sound 704

11.3 Categories of Compressible Flow 707

11.4 Isentropic Flow of an Ideal Gas 711

11.4.1 Effect of Variations in Flow Cross-Section Area 712

11.4.2 Converging-Diverging Duct Flow 714

11.4.3 Constant-Area Duct Flow 732

11.5 Nonisentropic Flow of an Ideal Gas 734

11.5.1 Adiabatic Constant Area Duct Flow with Friction （Fanno Flow） 734

11.5.2 Frictionless Constant Area Duct Flow with Heat Transfer （Rayleigh Flow） 749

11.5.3 Normal Shock Waves 759

11.6 Analogy Between Compressible and Open-Channel Flows 772

11.7 Two-Dimensional Compressible Flow 773

References 776

Problems 777

12TURBOMACHINES 783

12.1 Introduction 784

12.2 Basic Energy Considerations 786

12.3 Basic Angular Momentum Considerations 790

12.4 The Centrifugal Pump 792

12.4.1 Theoretical Considerations 794

12.4.2 Pump Performance Characteristics 798

12.4.3 Net Positive Suction Head （NPSH） 800

12.4.4 System Characteristics and Pump Selection 802

12.5 Dimensionless Parameters and Similarity Laws 806

12.5.1 Special Pump Scaling Laws 809

12.5.2 Specific Speed 811

12.5.3 Suction Specific Speed 811

12.6 Axial-Flow and Mixed-Flow Pumps 812

12.7 Fans 814

12.8 Turbines 815

12.8.1 Impulse Turbines 817

12.8.2 Reaction Turbines 827

12.9 Compressible Flow Turbomachines 831

12.9.1 Compressors 832

12.9.2 Compressible Flow Turbines 836

References 839

Problems 840

A UNIT CONVERSION TABLES 850

B PHYSICAL PROPERTIES OF FLUIDS 854

C PROPERTIES OF THE U.S. STANDARD ATMOSPHERE 860

D ALTERNATE METHOD FOR DETERMINATION OF PI TERMS 862

E COMPRESSIBLE FLOW TABLES FOR AN IDEAL GAS 866

ANSWERS 877

INDEX 885