Download or read book The Use of a Laser Doppler Velocimeter in Supersonic Flow written by William Joseph Yanta and published by . This book was released on 1971 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented for an experimental program which investigated the application of an LDV technique in supersonic flows. This paper presents an analysis of the behavior of light-scattering particles in rapidly accelerating or shock decelerated flows, an evaluation of particle production techniques and the results of several velocity measurements. Measurements included the velocity distribution along the nozzle centerline and flow over a diamond airfoil in a Mach 3 tunnel and velocity profiles for a turbulent boundary layer in a Mach 4.8 facility. It is demonstrated that LDV measurements can be made consistently with errors of less than five percent if the particle lag is considered. (Author).
Download or read book The Use of a Laser Doppler Velocimeter in Supersonic Flow written by William J. Yanta and published by . This book was released on 1971 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented for an experimental program which investigated the application of an LDV technique in supersonic flows. This paper presents an analysis of the behavior of light-scattering particles in rapidly accelerating or shock decelerated flows, an evaluation of particle production techniques and the results of several velocity measurements. Measurements included the velocity distribution along the nozzle centerline and flow over a diamond airfoil in a Mach 3 tunnel and velocity profiles for a turbulent boundary layer in a Mach 4.8 facility. It is demonstrated that LDV measurements can be made consistently with errors of less than five percent if the particle lag is considered. (Author).
Download or read book Laser Doppler Velocimeter Application in Supersonic Boundary Layer Flow written by J. C. Donaldson and published by . This book was released on 1987 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser Doppler velocimeter techniques have been investigated for nonintrusive measurements of cone boundary-layer mean-velocity profiles in supersonic flow. The investigation was performed in the AEDC Supersonic Wind Tunnel (A) at a free-stream Mach number of 4, using olive-oil droplets to seed the tunnel flow. The basis for the evaluation of the LDV results was a set of velocity profiles obtained using conventional probing techniques. Laminar, transitional, and turbulent boundary layers on a 7-deg (half-angle) sharp-cone model were included in this study. The results obtained in this investigation demonstrate that mean-velocity profiles can be obtained within acceptable limits of uncertainty provided (1) seed particles of appropriate size are found in tunnel flow or can be added to the flow and (2) a systematic editing procedure is available, when the results are evaluated, to eliminate velocities of relatively low probability and effects of spurious noise. (Author).
Download or read book Application of Laser Doppler Velocimeter to Chemical Vapor Laser System written by Luther R. Gartrell and published by . This book was released on 1993 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Laser Doppler Velocimeter Measurements of the Velocity Distribution in a Supersonic Jet Mixing with a Subsonic Outer Flow written by H. Tracy Jackson (Jr) and published by . This book was released on 1975 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional laser doppler velocimeter measurements were made of the velocity distribution in a supersonic inner jet mixing with a subsonic outer flow. Experimental data for mean flow velocities (u, v, w), turbulent intensities ((u') squared, (v') squared, (w') squared), and turbulent velocity correlations (u'v', u'w', v'w) are presented for both hot and cold exhaust plumes produced by a small kerosene/gaseous oxygen rocket engine operating at nominal chamber pressures of 50 and 150 psig. The outer flow was maintained at 200 ft/sec. Velocity profiles were obtained in the radial direction at various axial locations (X/D sub E=2.4, 4.8, 8.4, 11.3, and 14.2). The velocity profile along the centerline of the jet was obtained for the cold flows and showed the presence of shock waves at various axial locations. (Author).
Download or read book Laser Doppler Velocimeter Measurements of Boundary Layer Velocity and Turbulent Intensities in Mach 2 5 Flow written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-05 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, the interest in developing a high-speed civil transport has increased. This has led to an increase in research activity on compressible supersonic flows, in particular the boundary layer. The structure of subsonic boundary layers has been extensively documented using conditional sampling techniques which exploit the knowledge of both u and v velocities. Researchers using these techniques have been able to explore some of the complex three-dimensional motions which are responsible for Reynolds stress production and transport in the boundary layer. As interest in turbulent structure has grown to include supersonic flows, a need for simultaneous multicomponent velocity measurements in these flows has developed. The success of conditional analysis in determining the characteristics of coherent motions and structures in the boundary layer relies on accurate, simultaneous measurement of two instantaneous velocity components. Sewell, Jesse and Chew, Larry Unspecified Center NAG1-1402...
Download or read book Measurements in the Turbulent Boundary Layer at Constant Pressure in Subsonic and Supersonic Flow Part II Laser Doppler Velocity Measurements written by Paul E. Dimotakis and published by . This book was released on 1979 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been carried out using laser-Doppler velocimetry in conjunction with Pitot and surface-friction instrumentation for the measurement of the mean flow, the velocity fluctuations, and the Reynolds stresses in turbulent boundary layers at constant pressure in subsonic and supersonic flows. Part I of this work was a detailed analysis of the mean flow as observed using Pitot-tube, Preston-tube, and floating-element balance instrumentation. The present work (Part II) is a description of both the mean and the fluctuating components of the flow, and of the Reynolds stress as observed using a dual forward-scattering laser-Doppler velocimenter. A detailed description of the instrument, and of the data analysis techniques, have been included in order to fully document the data. A detailed comparison is made between the laser-Doppler results and those presented in Part I, and an assessment is made of the ability of the laser-Doppler velocimeter to measure the details of the flows involved.
Download or read book Development of a Laser Doppler Velocimetry System for Supersonic Jet Turbulence Measurements written by Alex Karns and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of military style exhaust nozzles to further understand their acoustic characteristics has been the recent focus of the Pennsylvania State University high-speed jet aeroacoustics facility. Advanced measurement techniques are required to study the turbulence characteristics of the flow field. Development of a laser Doppler velocimetry system would allow for these measurements to be made non-intrusively.Development of the laser Doppler velocimetry system required research and testing of each component as it was placed into the system. Development was split into two portions: fundamental or basic concepts and components, and advanced components. During these stages, many components, such as the transmitting and receiving probes, were fabricated, procedures were developed, and calibration of the transmitting probe was completed.Once the development stages were complete, the laser Doppler velocimetry system was used to measure subsonic flows of a cold air exhaust jet. Velocity measurements proved to be accurate to within 2% of calculated jet Mach numbers with discrepancies of up to 6% at Mach numbers approaching 1 at x/D of 2. Comparison of axial turbulence intensity data to previous studies yielded less favorable result possibly due to use of the exhaust fan, but this hypothesis cannot be proven without more experiments.Parametric studies were also on the ratio of the injection pressure ratio to the nozzle pressure ratio and the exhaust fan power determine their effects of seeding on measurement values. It was determined that ratio of the injection pressure ratio to the nozzle pressure ratio had negligible effect on the measurements except at a value of 1 where the axial turbulence intensity was up to 6% different than the other measurements. However, the ratio was found to have an inverse relationship to the number of validated burst particles per unit time. The power of the exhaust fan created differences in the measurement of up to 3% at x/D greater than 6, with higher values of Mach number and lower values of axial turbulence intensity at the exhaust fan power of 15%. However, it is difficult to draw conclusions with only two sets of data.
Download or read book Application of a Laser doppler Technique to the Measurement of Particle Velocity in Gas particle Two phase Flow written by Stanford University. Department of Aeronautics and Astronautics and published by . This book was released on 1966 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: In chemical propulsion, the use of metallic fuel constituents burning to particulate refractory oxides in rocket engines has forced attention to the understanding of two-phase nozzle expansion processes. In this study light from a helium-neon laser was reflected both from a fixed target and from moving particles. A lens concentrated the laser light and the light back-scattered from the particles was picked up by the same lens and directed into a Fabry-Perot scanning plate interferometer. The interferometer limited observation at any moment to those particles whose Doppler shifted frequency coincided with the interferometer transmission frequency. The light from the fixed target provided a frequency reference system, and calibrated movement of the interferometer mirror spacing provided continuous examination of velocity. Data in the form of lightscattering and number count vs velocity has been obtained for water droplets in subsonic flow, for aluminum spheres and alumina abrasive in cold supersonic flow and for aluminum and magnesium oxide in hot supersonic flow. Number count-velocity data was found to be a complicated function of particle size distribution and vector velocity distribution as well as instrument characteristics.
Download or read book Turbulence Measurements with a Laser Doppler Velocimeter written by William Joseph Yanta and published by . This book was released on 1973 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence measurements with a Laser Doppler Velocimeter (LDV) using the dual scatter or differential Doppler mode have been made in a subsonic, fully developed channel flow. The measurements were made using only those light scattering particles occurring naturally in air. Results include mean velocity profiles, turbulence intensities, Reynolds stress distributions and a skewness measurement of the velocity distribution function across the channel. Statistical techniques were used to obtain the various turbulence parameters. Guidelines have been established for the amount of data needed to obtain results with a specified accuracy and confidence level. Measurements have also been made to determine the particle-size distribution. An aerodynamic means was used to determine the size distribution, in contrast to the usual optical procedures. (Modified author abstract).
Download or read book The Use of the Laser Doppler Velocimeter for Flow Measurements written by Warren H. Stevenson and published by . This book was released on 1972 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Doppler Velocimeter Measurements in High Speed Flows written by H. Doyle Thompson and published by . This book was released on 1974 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three year research program covering the development and use of a Laser Doppler Velocimeter (LDV) for high speed flow measurements is described. The current configurations of the LDV optics and the high frequency signal processors are discussed. LDV measurements made in two-dimensional transonic nozzles and in the turbulent wake of an axisymmetric supersonic nozzle are presented. These are compared with previous experimental and analytical results. Excellent agreement is found to exist. Measurement problems presented by flows of extremely high turbulence intensity are illustrated and means for resolving them are discussed.
Download or read book Doppler Global Velocimetry Measurements for Supersonic Flow Fields written by James F. Meyers and published by BiblioGov. This book was released on 2013-07 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of Doppler Global Velocimetry (DGV) to high-speed flows has its origins in the original development of the technology by Komine et al (1991). Komine used a small shop-air driven nozzle to generate a 200 m/s flow. This flow velocity was chosen since it produced a fairly large Doppler shift in the scattered light, resulting in a significant transmission loss as the light passed through the Iodine vapor. This proof-of-concept investigation showed that the technology was capable of measuring flow velocity within a measurement plane defined by a single-frequency laser light sheet. The effort also proved that velocity measurements could be made without resolving individual seed particles as required by other techniques such as Fringe- Type Laser Velocimetry and Particle Image Velocimetry. The promise of making planar velocity measurements with the possibility of using 0.1-micron condensation particles for seeding, Dibble et al (1989), resulted in the investigation of supersonic jet flow fields, Elliott et al (1993) and Smith and Northam (1995) - Mach 2.0 and 1.9 respectively. Meyers (1993) conducted a wind tunnel investigation above an inclined flat plate at Mach 2.5 and above a delta wing at Mach 2.8 and 4.6. Although these measurements were crude from an accuracy viewpoint, they did prove that the technology could be used to study supersonic flows using condensation as the scattering medium. Since then several research groups have studied the technology and developed solutions and methodologies to overcome most of the measurement accuracy limitations.
Download or read book Development Testing and Application of a Three dimensional Laser Doppler Velocimeter for the Measurement of Gas Flows written by C. E. Fuller and published by . This book was released on 1970 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Papers on Laser Doppler Velocimetry written by Ronald J. Adrian and published by SPIE-International Society for Optical Engineering. This book was released on 1993 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Two Component Simultaneous LDV Laser Doppler Velocimeter Turbulence Measurements in an Axisymmetric Nozzle Afterbody Subsonic Flow Field with a Cold Underexpanded Supersonic Jet written by and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test was conducted to obtain nonintrusive measurements in the flow field about an axisymmetric nozzle afterbody with a cold, underexpanded jet, M sub j=1.563, in a parallel free stream, M sub alpha = 0.6. Reynolds shear stress and two components of mean velocity and turbulence intensity were measured using a two-color Bragg-diffracted laser Doppler velocimeter. Additional experimental data include the afterbody surface pressure distribution and laser vapor screen flow visualization of the jet plume. A multiple seeding technique was used to investigate the bimodal velocity probability distributions observed in the jet mixing region. (Author).
Download or read book Design Considerations for a 3 D Laser Doppler Velocimeter for Studying Gravity Waves in Shallow Water written by Robert J. Hallermeier and published by . This book was released on 1973 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
