Acoustic Particle Velocity Measurements using Lasers
Principles, Signal Processing And Applications
Publication Date: March 2014 Hardback 160 pp.
This book concerns the presentation of particle velocity measurement for acoustics using lasers, including Laser Doppler Velocimetry (LDV or Anemometry (LDA)) and Particle Imagery Velocimetry (PIV).
The author presents the importance of measuring acoustic velocity, particularly when acoustics is nonlinear, as well as characterizing the near fields. However, these applications need to use non-invasive sensors. Some optical techniques, initially developed for fluid mechanics, have been adapted to the field of acoustics in recent years. This book summarizes 15 years of research in this area, highlighting the improvements that have been made, particularly in signal processing, and showing applications for which they have proven to be innovative.
Chapter 1 outlines the acoustic equations, focusing on particle velocity and particle displacement. The second chapter presents one- and two-dimensional signal processing elements useful for measuring acoustic velocity with lasers. The third chapter presents the LDV set-up for acoustic and aeroacoustic measurements. Chapter 4 presents the PIV method for acoustic settings. The limitations of its use are experimentally investigated in the case of low acoustic levels. Key applications known today in scientific literature are presented throughout Chapters 3 and 4. The direct measurement of the acoustic boundary layer, acoustic streaming or the propagation in flow involved in thermoacoustics or aeroacoustics are presented. In the conclusion to the book, the performance of LDV and PIV measurement are compared and some future prospects are given.
1. Summary of Acoustic Equations.
2. Some Topics on Signal Processing.
3. LDV for Acoustics.
4. PIV for Acoustics.
About the Authors
Jean-Christophe Valière is Professor at the University of Poitiers in France and a member of the Institut “Polytechnique Poitevin de Recherche et d’Ingénierie en Mécanique, Matériaux et Energétique” (Pprime) affiliated with the CNRS. His research is focused on signal processing and acoustics with applications to nonlinear acoustics and aeroacoustics. He also contributes to historical acoustics in collaboration with archaeologists.