Preface page ................................................... xi
PART ONE GENERAL CONCEPTS
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
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
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