Laser Metrology in Fluid Mechanics: Boutier/Laser Metrology in Fluid Mechanics

In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes. The principles and characteristics of the different techniques available in laser metrology are described in detail in this book. Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption spectroscopy by tunable laser diodes, which are generally better suited for high velocity flows. The size determination of particles by optical means, a technique mainly applied in two-phase flows, is the subject of another chapter, along with a description of the principles of light scattering. For each technique the basic principles are given, as well as optical devices and data processing. A final chapter reminds the reader of the main safety precautions to be taken when using powerful lasers. Content: Chapter 1 Basics on Light Scattering by Particles (pages 1–66): Fabrice Onofri and Severine Barbosa Chapter 2 Optical Particle Characterization (pages 67–158): Fabrice Onofri and Severine Barbosa Chapter 3 Laser?Induced Fluorescence (pages 159–222): Fabrice Lemoine and Frederic Grisch Chapter 4 Diode Laser Absorption Spectroscopy Techniques (pages 223–270): Ajmal Mohamed Chapter 5 Nonlinear Optical Sources and Techniques for Optical Diagnostic (pages 271–306): Michel Lefebvre Chapter 6 Laser Safety (pages 307–320): Jean?Michel Most Laser Metrology in Fluid Mechanics......Page 2 Copyright......Page 3 Table of Contents......Page 4 Preface......Page 9 Introduction......Page 10 1.1. Introduction......Page 11 1.2.1. Maxwell’s equations......Page 12 1.2.2. Harmonic electromagnetic plane waves......Page 14 1.2.3. Optical constants......Page 19 1.2.4. Light scattering by a single particle......Page 21 1.3.1. Lorenz?Mie or Mie theory......Page 26 1.3.2. Debye and complex angular momentum theories......Page 36 1.4.1. Rayleigh theory......Page 39 1.4.2. Discrete dipole approximation......Page 41 1.5. The T-matrix method......Page 42 1.6. Physical or wave optics models......Page 44 1.6.1. Huygens?Fresnel integral......Page 45 1.6.2. Fraunhofer diffraction theory for a particle with a circular cross section......Page 47 1.6.3. Airy theory of the rainbow......Page 50 1.6.4. Marston’s physical-optics approximation......Page 54 1.7. Geometrical optics......Page 57 1.7.2. Calculation of the intensity of rays......Page 58 1.7.3. Calculation of the phase and amplitude of rays......Page 59 1.8.1. Scattering by an optically diluted particle system......Page 60 1.8.2. Multiple scattering......Page 61 1.8.3. Monte Carlo method......Page 62 1.10. Bibliography......Page 67 2.1. Introduction......Page 76 2.2.1. Diameter, shape and concentration......Page 78 2.2.2. Statistical representation of particle size data......Page 79 2.2.3. Concentrations and fluxes......Page 83 2.3.1. Physical principles and measured quantities......Page 84 2.3.2. Nature and procedure to achieve statistics......Page 85 2.4.1. Principle......Page 86 2.4.2. Modeling the phase?diameter relationship......Page 90 2.4.3. Experimental setup and typical results......Page 96 2.4.4. Conclusion......Page 99 2.5. Ellipsometry......Page 100 2.6.1. Principle......Page 102 2.6.2. Modeling and inversion of diffraction patterns......Page 104 2.6.3. Typical experimental setup and results......Page 107 2.6.4. Conclusion......Page 109 2.7.1. Similarities to forward diffraction......Page 110 2.7.2. Rainbow diffractometry......Page 111 2.7.3. Near-critical-angle diffractometry......Page 116 2.8.1. Principle and classical setup......Page 121 2.8.2. One-dimensional shadow Doppler technique......Page 123 2.8.3. Calculation of particle images using the point spread function......Page 124 2.8.4. Conclusion......Page 127 2.9.1. Principle......Page 128 2.9.2. Modeling the diameter?angular frequency relationship......Page 129 2.9.3. Conclusion......Page 135 2.10.1. Gabor holography for holographic films......Page 137 2.10.2. Inline digital holography......Page 138 2.10.3. Conclusion......Page 140 2.11.1. Principle......Page 141 2.11.2. Algebraic inverse method......Page 143 2.11.3. Experimental setup and conclusion......Page 145 2.12. Photon correlation spectroscopy......Page 148 2.13. Laser-induced fluorescence and elastic-scattering imaging ratio......Page 150 2.13.1. Principle......Page 151 2.13.2. Experimental setup and results......Page 152 2.14. Laser-induced incandescence......Page 153 2.15. General conclusions......Page 154 2.16. Bibliography......Page 155 3.1. Recall on energy quantification of molecules......Page 168 3.1.1. Radiative transitions......Page 171 3.1.4. Non-radiative transitions......Page 173 3.1.5. Line width......Page 174 3.2. Laser-induced fluorescence principles......Page 177 3.2.1. Absorption kinetics......Page 178 3.2.2. Fluorescence signal......Page 179 3.2.3. Fluorescence detection......Page 182 3.2.4. Absorption along optical path......Page 183 3.2.5. Fluorescence measurement device......Page 184 3.3.1. Generalities......Page 186 3.3.2. Diatomic molecules......Page 187 3.3.3. Poly-Atomic molecular tracers......Page 195 3.4.1. Principles and modeling......Page 211 3.4.3. Applications to concentration measurement......Page 214 3.4.4. Application to temperature measurement......Page 219 3.5. Bibliography......Page 227 4.1. High spectral resolution absorption spectroscopy in fluid mechanics......Page 231 4.2.1. Line profile......Page 234 4.2.2. Line strength......Page 236 4.3. Absorption spectroscopy bench......Page 237 4.3.1. Emitting optics......Page 238 4.3.2. Optical detection......Page 242 4.3.3. Spectra processing......Page 245 4.4. Applications in hypersonic......Page 253 4.4.1. F4 characteristics......Page 254 4.4.2. Setup installed at F4......Page 256 4.4.3. Results obtained at F4 and HEG......Page 257 4.5.1. Combustion applications......Page 258 4.5.2. Applications to atmospheric probing......Page 261 4.6.1. Multipass spectrometry......Page 262 4.6.2. Spectrometry in a resonant cavity......Page 265 4.7. Perspectives and conclusion on diode laser absorption spectroscopy......Page 269 4.7.2. Spatial resolution: use of probe in flow......Page 270 4.8. Bibliography......Page 272 5.1. Introduction to nonlinear optics......Page 278 5.2. Main processes in nonlinear optics......Page 279 5.2.1. Propagation effects......Page 280 5.2.2. Second- and third-order nonlinearities......Page 283 5.2.3. Phase matching notion......Page 287 5.3. Nonlinear sources for optical metrology......Page 289 5.3.1. Sum frequency generation and frequency doubling......Page 290 5.3.2. Raman converters......Page 292 5.3.3. Optical parametric generators and oscillators......Page 296 5.4.1. Introduction to four-wave mixing techniques......Page 303 5.4.2. Temperature and concentration measurements in four-wave mixing......Page 306 5.4.3. Velocity measurements in four-wave mixing......Page 308 5.5. Bibliography......Page 312 6.1. Generalities on laser safety......Page 314 6.2. Laser type and classification......Page 315 6.3.1. Biological risks......Page 317 6.3.2. Risks to the eye......Page 319 6.3.3. Risks to the skin......Page 321 6.3.5. Other biological risks......Page 322 6.4.2. Collective protection......Page 323 6.4.3. Individual protection......Page 325 6.5. Safety advice......Page 326 6.6. Human behavior......Page 327 Conclusion......Page 328 Nomenclature......Page 329 List of Authors......Page 334 Index......Page 336

In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes.
The principles and characteristics of the different techniques available in laser metrology are described in detail in this book.
Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption spectroscopy by tunable laser diodes, which are generally better suited for high velocity flows. The size determination of particles by optical means, a technique mainly applied in two-phase flows, is the subject of another chapter, along with a description of the principles of light scattering.
For each technique the basic principles are given, as well as optical devices and data processing. A final chapter reminds the reader of the main safety precautions to be taken when using powerful lasers.