Acoustic Particle Velocity Measurements Using Lasers: Principles, Signal Processing and Applications [Hardcover]

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.

PREFACE ix

CHAPTER 1. SUMMARY OF ACOUSTIC EQUATIONS 1

1.1. Basic equations 1

1.1.1. Fluid- and thermodynamics 1

1.1.2. Hypothesis of linear acoustics without losses 4

1.2. Acoustic equations 5

1.2.1. Linear acoustic equations with sources 5

1.2.2. Some remarks on acoustic sources 6

1.2.3. Without sources 7

1.2.4. Acoustic intensity and source power 9

1.2.5. Acoustic impedance and border conditions 10

1.3. Constants, units and magnitude orders of linear acoustics 12

1.4. Acoustic velocity measurement and applications 16

1.4.1. Velocity estimation from pressure gradient 16

1.4.2. Intensity estimation 17

1.4.3. Application to impedance estimation 18

1.5. Beyond linear equations 18

1.5.1. Acoustic equations with mean flow 19

1.5.2. High acoustic displacement 20

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