Laser Refractography (eBook)

Bronyus Simovich Rinkevichyus graduated from Moscow Power Engineering Institute with a degree in applied physical optics in 1965, defended his candidate's thesis in electronics at Moscow Power Engineering Institute in 1969, defended his doctoral thesis in optics at P.I. Lebedev Physical Institute of the Russian Academy of Sciences in 1980, Full Professor at V.A. Fabrikant Chair of Physics of Moscow Power Engineering Institute (Technical University), Doctor of Physics and Mathematics Science, author and co-author of over 300 scientific papers, 3 monographs, and 5 books published in the Russian and English languages, Member (affiliate) of IEEE,Full Member of D.S. Rozhdestvensky Optical Society, Full Member of the International Academy of Sciences of Higher School. The main fields of his scientific interests are coherent and informational optics, physical fundamentals of the laser diagnostics of flows, and history of science. Olga Anatolyevna Evtikhieva graduated from Moscow Power Engineering Institute with a degree in optoelectronic instruments in 1975, defended her candidate's thesis at Moscow Power Engineering Institute in 1980, Head of V.A. Fabrikant Chair of Physics of Moscow Power Engineering Institute (Technical University), Candidate of Technical Sciences, author and co-author of over 80 scientific papers and 4 books. The main fields of her scientific interest are applied and informational optics and laser refractometry. Irina Lvovna Raskovskaya graduated from Moscow Power Engineering Institute with a degree in radio physics in 1981, graduated from Moscow State University with a degree in theoretical physics in 1990, defended her candidate's thesis at Moscow State Technical University Stankin in 2005, Senior Researcher at V.A. Fabrikant Chair of Physics of Moscow Power Engineering Institute (Technical University), Candidate of Physics and Mathematics science, author and co-author of over 50 scientific papers. The main fields of her scientific interests are propagation of radio and optical waves in inhomogeneous media and laser measuring systems.

Contents 6
Conclusion 12
Introduction 14
1.1 Optical Refraction Methods for the Diagnostics of Various Media 14
1.2 Classical Schlieren Methods 17
1.3 Background-Oriented Schlieren Method 21
1.4 Laser-Computer Scanning and Multichannel Methods 23
1.5 Speckle Refractometry 26
1.6 Laser Refractography 27
References 31
Structured Laser Radiation (SLR) 33
2.1 Main Types of SLR 33
2.2 Gaussian Beams 34
2.2.1 Properties of Laser Radiation 34
2.2.2 Characteristics of the Gaussian Beam 36
2.2.3 Propagation of the Gaussian Beam through Optical Elements 39
2.3 Formation of SLR on the Basis of Optical Elements 41
2.3.1 Formation of the Laser Plane 41
2.3.2 Besselian Beams and Their Formation 45
2.4 Formation of SLR on the Basis of Diffraction Gratings 48
2.5 Formation of SLR on the Basis of Diffraction Elements 50
References 52
Physical Processes Giving Rise to Optical Inhomogeneities in Media 53
3.1 Temperature Field in Liquids 53
3.2 Acoustic Field in Liquids and Gases 59
3.3 Liquid Mixing Processes 62
3.3.1 Characteristics of Processes Taking Place in the Course of Mixing of Liquid Media 62
3.3.2 Methods for Visualization of Twisted Liquid Flows 64
3.4 Hydrodynamic Phenomena in Stratified Liquids 68
References 70
Refraction of Laser Beams in Layered Inhomogeneous Media 71
4.1 Geometrical Optics Approximation 71
4.1.1 Plane-Layered Medium 71
4.1.2 Spherically Layered Medium 74
4.2 Quasioptical Approximation for Laser Beams in Weakly Inhomogeneous Media 79
4.3 Numerical Modeling of the Propagation of a Beam in a Weak Exponential Temperature Inhomogeneity 85
References 89
Refraction of Structured Laser Radiation in Spherical Temperature Inhomogeneities 90
5.1 Refractograms of Plane Structured Laser Radiation for Typical Spherical Inhomogeneities 90
5.1.1 Refraction of Plane Structured Laser Radiation in a Spherical Inhomogeneity 90
5.1.2 Boundary Layer near a Hot Ball 92
5.1.3 Boundary Layer near a Cold Ball 95
5.1.4 Refractograms of a Transparent Spherical Inhomogeneity with a Temperature Gradient 99
5.1.5 Nonmonotonic Cylindrical and Spherical Inhomogeneities 101
5.2 Refractograms Based on Cylindrical SLR 104
5.3 Refractograms of Linear Multiple-Point SLR 106
References 111
Laser Refractographic Systems 112
6.1 Structural Elements of Laser Refractographic Systems 112
6.1.1 General Construction Principles of Refractographic Systems 112
6.1.2 Radiation Sources 113
6.1.3 Optical SLR-Forming and Positioning Units 113
6.1.4 Digital Refractogram Recording Equipment 115
6.2 Refractographic Systems with Various Types of SLR 116
6.2.1 Refractographic Systems Based on Plane-Structured Laser Radiation 116
6.2.2 Refractographic Systems Based on Conical and Cylindrical SLR 118
6.3 Refractographic System for Studying Free Convection in Liquids 120
6.3.1 Schematic Diagram of the Setup 120
6.3.2 Radiation Sources 121
6.3.3 Objects of Study and Temperature Monitoring Methods 122
6.3.4 Refractographic Measurement Procedures 124
6.4 Experimental 2- and 3D Refractograms in Boundary Layer Investigations 125
6.4.1 Gaussian Beam Refractograms in Transmitted and Scattered Light 125
6.4.2 Plane SLR Refractograms in Transmitted and Scattered Light 127
6.5 Refractographic System for Visualization of Liquid Mixing in Twisted Flows 130
6.5.1 Liquid-Mixing Visualization Procedure 130
6.5.2 Schematic Diagram of the Experimental Setup 131
6.5.3 Results of Experimental Studies 132
6.5.4 Refraction Pattern Processing Algorithm and Program 132
6.5.5 Liquid-Mixing Visualization with Two Crossed Laser Planes 134
6.6 Two-Perspective Laser Refractographic Systems for Monitoring Nonstationary Thermophysical Processes 135
6.6.1 Two-Perspective System for Obtaining Refractograms of Complex Objects 135
6.6.2 Two-Perspective System for Observing Refractograms in Scattered Light 138
6.6.3 System for Obtaining 4D Refractograms of Nonstationary Convection Currents in Liquids 141
6.7 Experimental Refractogram Library 142
References 144
Digital Refractogram Recording and Processing 146
7.1 Requirements for Image Recording and Processing Systems 146
7.2 Digital Laser Refractogram Recording Systems 147
7.2.1 Main Characteristics of Refractogram Recording Systems 147
7.2.2 Digital Photo Camera-Based Refractogram Recording System 148
7.2.3 SONY Video Camera-Based Refractogram Recording System 149
7.2.4 The model Videoscan-285/B-USB Digital Video System 150
7.3 Digital Laser Refractogram Models 162
7.4 Digital Refractogram Processing Methods 167
7.4.1 Parametric Estimation Methods 167
7.4.2 Weighting Algorithm Error Analysis 171
7.4.3 Numerical Refractogram Analysis Methods 176
7.5 Digital Refractogram Recording and Processing Recommendations 176
References 177
Laser Refractography—a Method for Quantitative Visualization of Optically Inhomogeneous Media 179
8.1 Principles of Quantitative Diagnostics of Inhomogeneity Profiles 179
8.2 Plane SLR Refractogram-Based Algorithm for Reconstructing the Temperature Field in a Spherical Boundary Layer 180
8.3 Results of the Reconstruction of the Temperature Profile of the Spherical Boundary Layer 184
8.4 Determination of the Parameters of an Exponential Model of a Boundary Layer at the Surface of a Heated Ball 188
8.5 Refractogram Library Construction Principles 191
References 196
Index 197