MEASUREMENT IN FLUID MECHANICSPDF电子书下载

PART ONE GENERAL CONCEPTS 3

1 Flow properties and basic principles 3

1.1 Forces，stresses，and the continuum hypothesis 3

1.2 Measurable properties 4

1.3 Flow velocity and velocity fields 5

1.4 Analytical description of flows 7

1.5 The choice of analytical approach 8

1.6 Similarity 11

1.7 Patterns of fluid motion 16

QUESTIONS AND PROBLEMS 17

REFERENCES 18

2 Measuring systems 19

2.1 Measuring systems and their components 19

2.2 Static response of measuring systems 23

2.3 Dynamic response of measuring systems 31

2.4 Distortion，loading，and cross-talk 40

QUESTIONS AND PROBLEMS 41

REFERENCES 43

3 Measurement uncertainty 45

3.1 Measurement errors 45

3.2 Measurement uncertainty 47

3.3 Uncertainty of derived properties 48

3.4 Rounding of reported values 51

QUESTIONS AND PROBLEMS 53

REFERENCES 54

4 Signal conditioning，discretization，and analysis 55

4.1 Fundamentals of electric and electronic circuits 55

4.2 Analogue signal conditioning 63

4.3 Discretization of analogue signals 68

4.4 Statistical analysis of signals 74

4.5 Frequency analysis of signals 84

QUESTIONS AND PROBLEMS 94

REFERENCES 95

5 Background for optical experimentation 98

5.1 The nature of light 98

5.2 Light propagation through media 101

5.3 Illumination 107

5.4 Light scattering 123

5.5 Light transmission，sensing，and recording 128

5.6 Characteristics of seeding particles 132

QUESTIONS AND PROBLEMS 142

REFERENCES 144

6 Fluid mechanical apparatus 147

6.1 Producing the desired flow 147

6.2 Changing the flow area 148

6.3 Flow management 151

6.4 Wind tunnels 154

6.5 Water tunnels and towing tanks 157

6.6 Turbulence and shear generation 159

6.7 Model testing 163

QUESTIONS AND PROBLEMS 165

REFERENCES 165

7 Towards a sound experiment 169

7.1 Planning the experiment 169

7.2 Safety 170

7.3 Qualitative assessment 170

7.4 Record keeping 174

7.5 Scientific ethics 175

QUESTIONS AND PROBLEMS 176

REFERENCE 176

PART TWO MEASUREMENT TECHNIQUES 179

8 Measurement of flow pressure 179

8.1 What exactly is pressure？ 179

8.2 Pressure-measuring instrumentation 180

8.3 Wall-pressure measurement 188

8.4 In-flow pressure measurement 193

8.5 Dynamic response and testing of pressure-measuring systems 200

QUESTIONS AND PROBLEMS 203

REFERENCES 205

9 Measurement of flow rate 208

9.1 Direct methods 208

9.2 Positive-displacement flow meters 209

9.3 Venturi，nozzle，and orifice-plate flow meters 211

9.4 Open-channel flow measurement 212

9.5 Averaging Pitot tubes 213

9.6 Laminar flow elements 213

9.7 Rotameters 214

9.8 Vortex-shedding flow meters 214

9.9 Drag flow meters 215

9.10 Turbine flow meters 215

9.11 Ultrasonic flow meters 216

9.12 Electromagnetic flow meters 217

9.13 Coriolis flow meters 217

9.14 Thermal-mass flow meters 218

9.15 Selection of flow meter 219

QUESTIONS AND PROBLEMS 219

REFERENCES 220

10 Flow visualization techniques 221

10.1 Overview 221

10.2 Marker techniques 222

10.3 Optical techniques 231

10.4 Radiation emission techniques 242

10.5 Enhancement of flow visualization records 243

QUESTIONS AND PROBLEMS 244

REFERENCES 246

11 Measurement of local flow velocity 249

11.1 Thermal anemometry 249

11.2 Laser Doppler velocimetry 264

11.3 Ultrasonic Doppler velocimetry 274

11.4 Particle displacement methods 275

11.5 Measurement of wind velocity 282

QUESTIONS AND PROBLEMS 284

REFERENCES 287

12 Measurement of temperature 290

12.1 A practical temperature scale 290

12.2 Thermometers 291

12.3 Dynamic response of thermometers 296

12.4 Thermochromic materials 299

12.5 Radiation emission methods 301

12.6 Optical techniques 304

QUESTIONS AND PROBLEMS 304

REFERENCES 305

13 Measurement of composition 307

13.1 Sample analysis 307

13.2 Thermal probes 310

13.3 Electric conductivity probes 311

13.4 Light-scattering methods 312

13.5 Laser-induced fluorescence 316

13.6 Particulate measurement 318

13.7 Void measurement 321

QUESTIONS AND PROBLEMS 323

REFERENCES 324

14 Measurement of wall shear stress 328

14.1 Estimates from measured velocity profiles 328

14.2 Estimates from pressure differences 332

14.3 Floating-element balances 335

14.4 Thermal techniques 336

14.5 Electrochemical method 338

14.6 Optical techniques 339

QUESTIONS AND PROBLEMS 342

REFERENCES 343

15 Outlook 345

Index 349