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.
1. Basics on Light Scattering by Particles, Fabrice Onofri and Séverine Barbosa.
2. Optical Particle Characterization, Fabrice Onofri and Séverine Barbosa.
3. Laser-Induced Fluorescence, Fabrice Lemoine and Frédéric Grisch.
4. Diode Laser Absorption Spectroscopy Techniques, Ajmal Mohamed.
5. Nonlinear Optical Sources and Techniques for Optical Diagnostic, Michel Lefebvre.
6. Laser Safety, Jean-Michel Most.
Alain Boutier is a member of the AFVL (French Association of Laser Velocimetry) and was the Assistant to the General Scientific Director for Office National d’Etudes et de Recherches Aérospatiales – ONERA (the French national office for study and research into aerospace).