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Development Of A Laser Doppler Velocimetry System For Supersonic Jet Turbulence Measurements
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Book Synopsis Development of a Laser Doppler Velocimetry System for Supersonic Jet Turbulence Measurements by : Alex Karns
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.
Book Synopsis The Use of a Laser Doppler Velocimeter in Supersonic Flow by : William Joseph Yanta
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).
Book Synopsis Turbulence Measurements with a Laser Doppler Velocimeter by : William Joseph Yanta
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).
Book Synopsis Two-Component Simultaneous LDV (Laser Doppler Velocimeter) Turbulence Measurements in an Axisymmetric Nozzle Afterbody Subsonic Flow Field with a Cold, Underexpanded Supersonic Jet by :
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).
Book Synopsis Turbulence Measurements with a Laser Doppler Velocimeter by : William J. Yanta
Download or read book Turbulence Measurements with a Laser Doppler Velocimeter written by William J. Yanta and published by . This book was released on 1973 with total page 240 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).
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722335045 Total Pages :34 pages Book Rating :4.3/5 (35 download)
Book Synopsis Laser Doppler Velocimeter Measurements of Boundary Layer Velocity and Turbulent Intensities in Mach 2. 5 Flow by : National Aeronautics and Space Administration (NASA)
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...
Book Synopsis Doppler Global Velocimetry Measurements for Supersonic Flow Fields by : James F. Meyers
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.
Book Synopsis Development Testing and Application of a Three-dimensional Laser Doppler Velocimeter for the Measurement of Gas Flows by : C. E. Fuller
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:
Book Synopsis Application of Laser Doppler Velocimeter to Chemical Vapor Laser System by : Luther R. Gartrell
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:
Book Synopsis Laser Doppler Velocimeter Measurements in High Speed Flows by : H. Doyle Thompson
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.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Three Dimensional Laser Doppler Velocimeter Measurements of the Velocity Distribution in a Supersonic Jet Mixing with a Subsonic Outer Flow by : H. Tracy Jackson (Jr)
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).
Book Synopsis Doppler Global Velocimetry: Development of a Flight Research Instrumentation System for Application to Non-intrusive Measurements of the Flow Field by :
Download or read book Doppler Global Velocimetry: Development of a Flight Research Instrumentation System for Application to Non-intrusive Measurements of the Flow Field written by and published by . This book was released on 1994 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Velocimetry in Fluid Mechanics by : Alain Boutier
Download or read book Laser Velocimetry in Fluid Mechanics written by Alain Boutier and published by John Wiley & Sons. This book was released on 2012-10-22 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: In fluid mechanics, velocity measurement is fundamental in order to improve the behavior knowledge of the flow. Velocity maps help us to understand the mean flow structure and its fluctuations, in order to further validate codes. Laser velocimetry is an optical technique for velocity measurements; it is based on light scattering by tiny particles assumed to follow the flow, which allows the local fluid flow velocity and its fluctuations to be determined. It is a widely used non-intrusive technique to measure velocities in fluid flows, either locally or in a map. This book presents the various techniques of laser velocimetry, as well as their specific qualities: local measurements or in plane maps, mean or instantaneous values, 3D measurements. Flow seeding with particles is described with currently used products, as well as the appropriate aerosol generators. Post-processing of data allows us to extract synthetic information from measurements and to perform comparisons with results issued from CFD codes. The principles and characteristics of the different available techniques, all based on the scattering of light by tiny particles embedded in the flow, are described in detail; showing how they deliver different information, either locally or in a map, mean values and turbulence characteristics.
Book Synopsis Development of a Laser Doppler System for the Detection, Tracking, and Measurement of Aircraft Wake Vortices by :
Download or read book Development of a Laser Doppler System for the Detection, Tracking, and Measurement of Aircraft Wake Vortices written by and published by . This book was released on 1975 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Marshall Space Flight Center (MSFC) has developed a scanning laser doppler vortex system (SLDVS) for use as an aircraft trailing vortex detection, tracking, and measuring system. This report describes the SLDVS design, development, and checkout at MSFC Previous efforts at MSFC had demonstrated the capability of laser Doppler systems to accurately measure remote wind velocity and turbulence. Tradeoff studies were performed to determine the optimum design parameters that met the program objectives. Computer simulations of the SLDVS performance were used in determining the optimum design parameters. The SLDVS scans both in range and angle. A real-time vortex display system is provided.
Book Synopsis A Laser Doppler Velocimeter Approach for Near-wall Three-dimensional Turbulence Measurements by :
Download or read book A Laser Doppler Velocimeter Approach for Near-wall Three-dimensional Turbulence Measurements written by and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Diagnostic Development and Measurement and Modeling of Turbulent Flowfields of Jets and Wakes by : A. J. Lightman
Download or read book Laser Diagnostic Development and Measurement and Modeling of Turbulent Flowfields of Jets and Wakes written by A. J. Lightman and published by . This book was released on 1983 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two-dimensional laser Doppler anemometer was designed to take measurements in a ducted coaxial flow system having a centerbody separating the jets. The measurements, made in isothermal flow, can be categorized as: central jet only (C02); annular jet only (air); and, combined central and annular jet flow. Radial profiles of the axial and radial/azimuthal velocity were obtained. The central jet only condition approximates a free jet since the central jet diameter is much smaller than the centerbody or duct diameter (1:29.3: 53.2). Measurements of the jet development (diameter, turbulence intensity, etc.) were compared with previous free jet studies. In a study of the isotropy of the turbulent fluctuations it was determined that fully developed turbulent flow begins further downstream than anticipated. Velocity profiles were combined with gas sampling measurements to ascertain jet entrainment. Results show a linear growth of the entrained mass starting at the entrance plane. Downstream (20 diameters) the rate of growth increases to match past studies in that region. The annular jet flow creates a recirculation vortex in the wake of the centerbody. The flowfield was mapped and the streamlines describing the flow were obtained throughout the recirculating flow and further downstream. The location and strength of the vortex center was determined. Velocity scanes were combined to obtain profiles of the average radial and azimuthal components that were directly measured. The interaction of the recirculating annular air jet and the central get was examined. Profiels of the velocity field were obtained for several central jet flow conditions. A normalization plot of the location of the central jet stagnation location agreed well with earlier measurements using a one-dimensional laser doppler anemometer and a different central jet nozzle.
