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This volume consists of papers selected from the proceedings of the Fifth International Symposium on Applications of Laser Techniques to Fluid Mechanics, held at the Calouste Gulbenkian Foundation in Lisbon from 9 to 12 July, 1990. Relative to previous meetings in the Lisbon series the scope of this symposium was broadened by expanding the topical coverage to include all laser techniques used in fluid mechanics. This change recognized the trend amongst experimental fluid dynamicists to employ laser techniques for the mea surement of many different quantities, including concentration, temperature, particle size, and velocity, and the need for researchers to have a forum in which to communicate their work and share their common interests. The Fifth Symposium contained twenty-three sessions of formal presentations and a lively Open Forum ses sion. In addition, Dr. H. J. Pfeiffer organized a special Workshop on the Use of Computers in Flow Mea surements which contained five sessions on frequency domain processors, correIa tors, special detectors, and biasing.

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I - Scalar Transport.- Four-Dimensional Laser Induced Fluorescence Measurements of Conserved Scalar Mixing in Turbulent Flows.- Planar Laser-Induced Fluorescence Scalar Measurements in a Turbulent Jet.- Simultaneous Measurement of Velocity and Temperature of Water Using LDV and Fluorescence Technique.- Simultaneous, Real-Time Line Measurements of Concentration and Velocity in Turbulent Flows.- Digital Particle Image Thermometry and Its Application to a Heated Vortex-Ring.- Temperature Measurement in a Asymmetric Thermal Flow Field by Laser Holographic Interferometry.- II - Two-Phase Flow, Size and Velocity.- LDA Measurements of Plastic and Elastic Collisions of Small Particles with Metal Surfaces.- The Influence of Swirl on the Particle Dispersion in a Pipe Expansion Flow.- Flow Measurements in a Liquid Fuelled Burner.- Fringe Count Limitations on the Accuracy of Velocity and Mass Flux in Two-Phase Flows.- Measurement of Size and Velocity Distributions of Droplets Produced by Bubbles Bursting.- Sensitivity of Dropsize Measurements by Phase Doppler Anemometry to Refractive Index Changes in Combusting Fuel Sprays.- LDA Measurement of Gasoline Droplet Velocities and Sizes at Intake-Valve Annular Passage in Steady Flow State.- Measurement of Fuel Injector Spray Flow of I.C. Engine by FFT Based Phase Doppler Anemometer - An Approach to the Time Series Measurement of Size and Velocity.- III - Instrumentation.- Signal Processing Considerations for Laser Doppler and Phase Doppler Applications.- Improved Optical Systems for Velocimetry and Particle Sizing Using Semiconductor Lasers and Detectors.- A Photothermal Velocimeter Using an Optical Fibre Heterodyne Interferometer with Phase Differentiation at Two Points.- Two-Point Adapter for LDA Probe Using Multimode Fibers.- Velocity Measurement Using Fibre Optic Sagnac Interferometers.- Semiconductor Long-Range Anemometer Using a 5 mW Diode Laser and a Pin Photodiode.- An Experimental Evaluation of a Novel Method of Using Localized Laser Heating in the Determination of Wall Shear Stress.- IV -; Whole-Field Velocimetry.- Application of Particle Image Velocimetry to Transonic Flows.- Studies of Liquid Turbulence Using Double-Pulsed Particle Correlation.- Turbulent Intensity Evaluation with PIV.- Instantaneous Particle Image Velocimetry with Electronic Specklegram.- Measurement of Dynamics of Coherent Flow Structures Using Particle Image Velocimetry.- Two-Phase Flow Velocity Measurements Using Automated-Based Imaging Pulsed Laser Velocimetry.- Mixing Flow in a Cylindrical Vessel Agitated by a Bubbling Jet - Application of Image Processing Velocimetry.- Visualization and Measurement of Detailed Velocity Field in U-Bend and Branched Tube Using Laser-Induced Fluorescence Method.- Photobleaching Flow Visualization.

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