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Full-Text Articles in Optics
Particle Image Velocimetry And Analysis Methods Using Cleanly Seeded Particles In Supersonic Flow, Paul A. Gulotta
Particle Image Velocimetry And Analysis Methods Using Cleanly Seeded Particles In Supersonic Flow, Paul A. Gulotta
Theses and Dissertations
Particle Image Velocimetry (PIV) was successfully conducted in the Air Force Research Lab Mach 3/ Mach 6 Facility (M3M6F) for the first time. Particle response experiments evaluating the performance of dry ice particles across an oblique shock wave were conducted using a 15 degree half-wedge in nominal Mach 3 flow. Solid carbon dioxide particles are generated through rapid expansion of liquid carbon dioxide via a small nozzle within a simple shroud tube or a tube containing static mixing elements. Particles are injected directly into the settling chamber of the Mach 3 tunnel. The particle response of carbon dioxide particles is …
Background-Oriented Schlieren Pattern Optimization, Jeffery E. Hartberger
Background-Oriented Schlieren Pattern Optimization, Jeffery E. Hartberger
Theses and Dissertations
This paper describes a test series to investigate background patterns used for the Background-Oriented Schlieren field density measurement technique. Several varying background patterns were substituted under similar fluid density conditions to visualize and isolate the effects of patterns in the background images. A qualitative comparison was completed of the flow visualization results of each background pattern to categorize background conditions that improved the flow visualization image. Changes in background patterns revealed significant changes in flow visualization. Pattern contrast, spacing and sizing all played large parts in the quality of the visual density gradient imaging during the test series.
Characterizing A Co-Flow Nozzle For Use In A Filtered Rayleigh Scattering System, David S. Miceli
Characterizing A Co-Flow Nozzle For Use In A Filtered Rayleigh Scattering System, David S. Miceli
Theses and Dissertations
Research was conducted on the flow field exiting a co-annular flow nozzle for use in filtered Rayleigh scattering flow visualizations. More specifically, the flow visualizations were of the flow field exiting a coflow nozzle and illuminated by a tunable, nominal 4.2 watt narrow line width Argon laser operating at 514.5nm. ND:YAG lasers are typically used in this application, but some of the properties of a tunable Argon laser make it an attractive alternative. Before generating flow visualizations, the coflow nozzle was characterized both experimentally and computationally. Due to a flow asymmetry in the outer annulus flow field, the nozzle was …
Flow Visualization Of A Turbulent Shear Flow Using An Optical Wavefront Sensor, Daniel W. Jewell
Flow Visualization Of A Turbulent Shear Flow Using An Optical Wavefront Sensor, Daniel W. Jewell
Theses and Dissertations
The research reported here investigated the use of a shearing interferometer (SI) wavefront sensor to determine the effects of shear-layer turbulence on an optical wavefront. A collimated helium-neon laser beam was propagated through a plane shear-layer produced by mixing helium and nitrogen at different velocities. Since the gases have different indices of refraction, the optical wavefront was distorted by different amounts by each gas. The SI measured the wavefront slope across the sampled area of the wavefront. The shear-layer was viewed from two orthogonal directions. This document contains shadow graphs, interference patterns imaged by each of the SI's six cameras, …