Acoustic Particle Velocity Measurements Using Lasers Principles, Signal Processing and Applications

by Valière, Jean-Christophe

• ISBN13: 9781848215627
• ISBN10: 1848215622
• Edition: 1st
• Format: Hardcover
• Copyright: 2014-05-12
• Publisher: Wiley-ISTE

Summary

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 objective is first to present the importance of measuring the acoustic velocity, especially when the acoustic equations are 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 a carrier of innovation.

Author Biography

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.

Table of Contents

1) Summary of acoustic equations

A brief recall of acoustic equations

Overview of velocity measurement difficulties (order of magnitude…). Some existing solutions (intrusives) are presented.

Problems encountered in acoustic measurements when velocity cannot be deduce from acoustic pressure.

Some example where acoustic velocity measurement is necessary (thermoacoustic, audio, aeroacoustic)

2) Some topics on signal processing

Main functions of signal processing (sampling theory, statistical signal processing, correlation, Fourier analysis).

Focused on the presentation of random sampling (for LDV)

Basic knowledge on 2D signal processing (for PIV)

3) LDV (or LDA) for acoustics

Optical devices used in fluid mechanics

Signal processing used in fluid mechanics

Necessity of the development of new signal processing techniques for acoustics

Presentation of the different approaches (Taylor 1976, Greated-Campbell 90’, Gervais 90’, Valière et al. 1998-2012)

Statistical study of the performance

4) PIV for acoustics

Presentation of existing devices

Presentation of classical image processing used in fluid mechanics

Study of the limitation of the signal processing in a context of acoustics

Presentation of specific use for acoustics

5) Comparison and some applications

Synthesis of the performance obtained by numerous authors.

Presentation on specific applications

Acoustic and acoustic streaming.

Measurement in boundary layer.

Radiation of loudspeakers.

Measurement of non-linearity of loudspeaker port.