Imaging Measurement Methods for Flow Analysis (eBook)

Prof. Dr.-Ing. Wolfgang Nitsche holds the chair of Aerodynamics at the Institute of Aeronautics and Astronautics of the Technische Universität Berlin, and is coordinator of the priority programme 1147 "Imaging Measurement Methods for Flow Analysis" funded by the DFG (German Research Foundation).

Title Page 2
Preface 6
Contents 8
List of Contributors 12
Principles of a Volumetric Velocity Measurement Technique Based on Optical Aberrations 22
Introduction 22
Measurement Principle 24
{/it Measurement Volume Size} 25
{/it Calibration of the Measurement Volume} 26
{/it Particle Image Fitting} 26
{/it Calibration with Particle Images} 28
Validation 28
Determination of the Flow Velocity 30
Conclusion and Outlook 30
References 31
TheWall-PIV Measurement Technique for Near Wall Flow Fields in Biofluid Mechanics 32
Introduction 32
Flow and Shear Stress Measurement Techniques 33
Wall-PIV 34
{/it Wall-PIV Setup} 34
{/it Flow Estimation Algorithm} 35
Error Estimation 36
Experimental Validation 37
Experiments 38
References 40
Laser Doppler Field Sensor for Two Dimensional Flow Measurements in Three Velocity Components 42
Introduction 42
Velocity Profile Sensor 44
Measurement of Inclined Trajectories and Accelerated Particles 45
Velocity Field Sensor 46
Conclusion and Outlook 48
References 49
Array Doppler Global Velocimeter with Laser Frequency Modulation for Turbulent Flow Analysis – Sensor Investigation and Application 52
Introduction 53
Measurement Principle 53
Measurement System 55
{/it General Set-Up and Calibration} 55
{/it Spatial Resolution} 56
{/it Temporal Resolution} 57
{/it Velocity Uncertainty} 57
Measurement Results 59
Conclusions 61
References 61
Self-calibrating Single Camera Doppler Global Velocimetry Based on Frequency Shift Keying 63
Introduction 63
Principle of DGV 64
Self-calibrating DGV Based on FSK-Techniques 65
System Setup 66
Measurements 67
{/it Spinning Disc} 67
{/it Flow Field} 68
Phase-Averaged Measurements 71
Conclusions 71
References 72
Recent Developments in 3D-PTV and Tomo-PIV 73
Introduction 73
Virtual Four Camera System 74
Multimedia Geometry 76
Tomographic PIV 78
Conclusion 81
References 81
3D Tomography from Few Projections in Experimental Fluid Dynamics 83
Introduction 83
Related Work 84
Reconstruction Algorithms 86
{/it Algebraic Reconstruction Techniques} 86
$l_{1}$-{/it Minimization and Linear Programming} 87
Design and Evaluation Criteria 87
Design Criteria 87
Evaluation Criteria 88
Numerical Results 90
Conclusions 91
References 92
Tomographic PIV for Investigation of Unsteady Flows with High Spatial and Temporal Resolution 93
Introduction 93
Tomographic PIV— Fundamentals 94
Application I: Time-Resolved Tomographic PIV in a Wind Tunnel 95
{/it Setup} 95
{/it Results} 96
Application II: Investigation of a Free Turbulent Jet Air Flow 97
{/it Setup} 97
{/it Results} 98
Application III: Investigation of a Turbulent Boundary Layer in a Water Tunnel 99
{/it Setup} 99
{/it Results} 100
Conclusion 101
References 102
Time-Resolved Two- and Three-Dimensional Measurements of Transitional Separation Bubbles 103
Introduction 103
Principle Description of Scanning PIV 104
The Three-Dimensional Flow Field on Top of a Finite Circular Cylinder 106
Temporally and Spatially Resolved Vortical Structures on an SD7003 Airfoil 107
Conclusion and Outlook 111
References 111
Coloured Tracer Particles Employed for 3-D Particle Tracking Velocimetry (PTV) in Gas Flows 113
Introduction 113
Quantifying the Properties of Coloured Tracer Particles 114
Colour Recognition by Artificial Neural Network 117
3-D Coordinates by Means of Photogrammetry 118
Re-building Trajectories 119
Experimental Setup 119
Results of 3D-PTV Involving Coloured Tracers 120
Conclusion 121
References 121
Two Scale Experiments via Particle Tracking Velocimetry: A Feasibility Study 123
Introduction 123
Method 125
Results 126
{/it Checks} 126
{/it Small Scale Results} 127
{/it Large Scale Results} 128
Summary 130
References 131
Extended Three Dimensional Particle Tracking Velocimetry for Large Enclosures 132
Introduction 132
Experiment 134
{/it The Barrel of Ilmenau} 134
{/it 3D PTV System} 134
{/it Tracer Particles} 136
{/it Camera System} 138
{/it Validation Measurement} 139
Results 139
Conclusion 141
References 142
High Density, Long-Term 3D PTV Using 3D Scanning Illumination and Telecentric Imaging 144
Introduction 144
Experimental Set-Up 145
{/it Mirror Drum Scanner} 146
{/it Telecentric Lenses} 146
Reconstruction Methods 146
{/it Camera Model} 147
{/it Epipolar Geometry} 147
{/it Calibration} 148
{/it Particle Tracking} 149
Results 149
Conclusions 152
References 152
Quantitative Measurements of Three-Dimensional Density Fields Using the Background Oriented Schlieren Technique 154
Introduction 154
Properties of BOS 155
Tomographic Reconstruction 158
Measurements at a Double Free Jet of Air 158
Density Measurement behind Straight Blades 160
Conclusions 162
References 162
Tomographic Reconstruction and Efficient Rendering of Refractive Gas Flows 164
Overview 165
Background Oriented Schlieren Imaging 165
Tomographic Reconstruction 168
Continous Refraction Rendering 169
Results 171
References 173
2D-Measurement Technique for Simultaneous Quantitative Determination of Mixing Ratio and Velocity Field in Microfluidic Applications 174
Introduction 174
Flow Field Analysis by 2D-Molecular Tagging Velocimetry 174
Reference Measurements and Taylor Dispersion 177
Determination of Species Concentrations by Planar Raman Scattering 179
Conclusions 181
References 182
Simultaneous, Planar Determination of Fuel/Air Ratio and Velocity Field in Single Phase Mixture Formation Processes 184
Introduction 184
The FARLIF Concept and Experimental Setup 185
FARLIF Verification with Toluene 186
FARLIF Verification with Near-Standard Fuel 188
Concept for Temperature Determination and Correction 190
Summary 191
References 192
Development of Imaging Laser Diagnostics for the Validation of LE-Simulations of Flows with Heat and Mass Transfer 194
Introduction 194
Raman Scattering 196
PIV and Ramanography in Liquid Mixing Processes 197
Mole Fraction and Temperature Analysis in Hydrogen Flows 198
Conclusion 201
References 201
Optical Measurements in the Wake of a Circular Cylinder of Finite Length at a High Reynoldsnumber 204
Introduction 204
Experimental Setup 205
Time Averaged Flow 206
Spectral Analysis 207
Proper Orthogonal Decomposition 207
Conclusion and Outlook 213
References 214
Surface Pressure and Wall Shear Stress Measurements on a Wall Mounted Cylinder 215
Introduction 215
Experimental Setup 216
{/it Pressure Measurements} 217
{/it Wall Shear Stress Measurements} 217
Results 220
Conclusion 223
References 224
Numerical Simulation and Analysis of the Flow Around aWall-Mounted Finite Cylinder 225
Background and Objectives 225
Approach and Project History 226
Numerical Setup and Methods 227
Selected Results and Findings 228
{/it Time-Averaged Flow Topology} 228
{/it Comparison to Experiments and Different Approaches} 229
{/it Proper Orthogonal Decomposition - POD} 229
{/it Particle and Structure Tracking} 231
{/it Harmonic Filtering} 232
Synthesis 233
Perspectives of the Numerical Database 233
References 234
Measurement of Distributed Unsteady Surface Pressures by Means of Piezoelectric Copolymer Coating 235
Introduction 235
Measuring Principle of the PSC Technique 236
Flow Measurements Around a Wall-Mounted Cylinder 237
{/it Experimental Set-Up} 237
{/it Phase-Averaged Measurements} 238
{/it Investigations with High Spatial and Temporal Resolution} 239
Conclusion 243
References 244
AeroMEMS Sensor Arrays for Time Resolved Wall Pressure and Wall Shear Stress Measurements 245
Introduction 245
AeroMEMS Sensors 246
{/it Sensor Design} 246
{/it Fabrication of the AeroMEMS Sensor Chips} 247
Wind Tunnel Experiments 248
{/it High-Frequency Transition Measurements} 248
{/it Surface Pressure Measurements on a Wall Mounted Cylinder Employing a 3D Multi-sensor Array} 249
Conclusion 252
References 253
Infrared-Based Visualization of Wall Shear Stress Distributions 255
Introduction 255
Experimental Setup 256
Visualization ofWall Shear Stress Distributions 257
Spatial Quantification ofWall Shear Stress Distributions 260
Conclusion 263
References 264
Variational Approaches to Image Fluid Flow Estimation with Physical Priors 265
Introduction 265
Unconstrained Variational Fluid Flow Estimation 266
Constrained Variational Fluid Flow Estimation 267
{/it Flow Estimation by Flow Control} 267
{/it Enforcing Temporal Coherency} 268
Constrained Fluid Flow Denoising in 3D 269
{/it Variational Approach} 269
{/it Numerical Experiments} 272
Conclusion and Further Work 273
References 273
Real-Time Approaches for Model-Based PIV and Visual Fluid Analysis 275
Introduction 275
Related Work 276
Model-Based Flow Reconstruction 277
{/it Flow Prediction and Correction} 278
{/it Vector Field Correction} 279
{/it Results} 279
Particle-Based Flow Visualization 282
Current and Future Work 283
References 284
Biocompatible Visualization of Flow Fields Generated by Microorganisms 286
Introduction 286
Materials and Methods 287
{/it Digital Micro Particle Image Velocimetry} 288
{/it Digital Micro Particle Tracking Velocimetry} 288
{/it Novel Neuronumerical Hybrid with a Priori Knowledge} 289
Results 289
{/it Digital Micro Particle Image Velocimetry} 289
{/it Digital Micro Particle Tracking Velocimetry} 292
{/it Novel Neuronumerical Hybrid with a Priori Knowledge} 293
Summary 293
References 294
Nonlinear Dynamic Phase Contrast Microscopy for Microflow Analysis 296
Introduction 296
Nonlinear Dynamic Phase Contrast Microscope 297
Features of Nonlinear Dynamic Phase Contrast Microscopy 298
{/it Contrast Enhancement} 299
{/it Spatial Resolution} 299
{/it Phase Sensitivity} 301
Optimized Data Acquisition for Flow Field Analysis 301
Photorefractive Velocimetry 302
Concentration Measurement in Microfluidic Mixing Processes 303
Summary 304
References 304
Spatiotemporal Image Analysis for Fluid Flow Measurements 306
Introduction 306
Extended Optical Flow Models 307
{/it Diffusion of Brightness} 308
{/it Exponential Brightness Change} 310
{/it Integration across Flow Profiles} 311
Solving the Flow Problem 312
{/it Local Spatiotemporal Approach} 312
{/it Trajectory-Based Approach} 313
Applications 315
{/it 3D-3C Measurements at the Free Air-Water Interface} 315
{/it Shear Flow at Moving Boundaries in Artificial Hearts} 316
{/it Viscous Shear at the Air-Water Interface} 316
{/it Molecular Tagging Velocimetry} 317
{/it Mixture Formation Analysis with Fluorescence Motion Analysis} 318
{/it Wall Shear Rates Using Thermography} 319
Conclusions 319
References 320
Extraction and Visualization of Flow Features 322
Introduction 322
Flow-Features Identification 323
Visualization of Vortices 324
{/it Vortex Segmentation} 324
{/it Vortex Visualization} 325
{/it Introducing Line Integral Convolution} 326
Vortex Tracking 327
Considering Vortex Dynamics 329
Conclusions 331
References 331
Author Index 332