Download or read book A Laser Velocity Measurement System for High temperature Wind Tunnels written by George R. Grant and published by . This book was released on 1970 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Velocimetry in the Low speed Wind Tunnels at Ames Research Center written by and published by . This book was released on 1984 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Laser Velocimeter to be Used in AEDC Wind Tunnels written by A. E. Lennert and published by . This book was released on 1970 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report summarizes a three-year analytical and experimental program to develop a laser Doppler velocity (LDV) instrument for measuring velocities of flowing fluids. The electro-optical instruments are being developed for enhancing the measuring capabilities in the AEDC wind tunnels. The basic design parameters of the input-aligned optics LDV system and, in particular, the development of a self-aligning system to obviate the basic problems inherent with previously conceived systems, are described in detail. The design and the progress are presented on a direct readout system to determine directly three orthogonal components of velocity. A number of significant proof-of-principle experiments covering a wide variety of flows, both liquid and gaseous, are discussed. Included are the results of a V/STOL wind tunnel calibration study verifying the superior performance of the LDV for velocity determinations and boundary-layer measurements. (Author).
Download or read book A Laser Velocimeter System for Large scale Aerodynamic Testing written by and published by . This book was released on 1984 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Velocity Measurements in the AEDC Low Speed Wind Tunnel V STOL Using a Laser Doppler Velocimeter written by F. H. Smith and published by . This book was released on 1970 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-house developed laser Doppler velocimeter (LDV) was used to make velocity measurements in a low speed wind tunnel. The installation and instrumentation are discussed, and velocity profiles obtained with the LDV are compared with those obtained using conventional techniques. A discussion on the factors which affect the accuracy of the LDV and improvements that would be desirable are also included. (Author).
Download or read book Doppler Global Velocimeter Development for the Large Wind Tunnels at Ames Research Center written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of an optical, laser-based flow-field measurement technique for large wind tunnels is described. The technique uses laser sheet illumination and charged coupled device detectors to rapidly measure flow-field velocity distributions over large planar regions of the flow. Sample measurements are presented that illustrate the capability of the technique. An analysis of measurement uncertainty, which focuses on the random component of uncertainty, shows that precision uncertainty is not dependent on the measured velocity magnitude. For a single-image measurement, the analysis predicts a precision uncertainty of +/-5 m/s. When multiple images are averaged, this uncertainty is shown to decrease. For an average of 100 images, for example, the analysis shows that a precision uncertainty of +/-0.5 m/s can be expected. Sample applications show that vectors aligned with an orthogonal coordinate system are difficult to measure directly. An algebraic transformation is presented which converts measured vectors to the desired orthogonal components. Uncertainty propagation is then used to show how the uncertainty propagates from the direct measurements to the orthogonal components. For a typical forward-scatter viewing geometry, the propagation analysis predicts precision uncertainties of +/-4, +/-7, and +/-6 m/s, respectively, for the U, V, and W components at 68% confidence. Reinath, Michael S. Ames Research Center...
Download or read book Hardening Doppler Global Velocimetry Systems for Large Wind Tunnel Applications written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of Doppler Global Velocimetry from a laboratory curiosity to a wind tunnel instrumentation system is discussed. This development includes system advancements from a single velocity component to simultaneous three components, and from a steady state to instantaneous measurement. Improvements to system control and stability are discussed along with solutions to real world problems encountered in the wind tunnel. This on-going development program follows the cyclic evolution of understanding the physics of the technology, development of solutions, laboratory and wind tunnel testing, and reevaluation of the physics based on the test results.Meyers, James F. and Lee, Joseph W. and Fletcher, Mark T. and South, Bruce W.Langley Research CenterHARDENING (SYSTEMS); WIND TUNNEL APPARATUS; LASER DOPPLER VELOCIMETERS; CCD CAMERAS; CALIBRATING; IODINE LASERS; ROTORS; NEODYMIUM LASERS; YAG LASERS; SUBSONIC WIND TUNNELS
Download or read book Flow Visualization and Laser Velocimetry for Wind Tunnels written by William W. Hunter and published by . This book was released on 1982 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Diagnostic Techniques written by J. C. F. Wang and published by . This book was released on 1973 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes a study of 3-D diagnostic techniques for measurements of flow velocity in the test section of a hypersonic wind tunnel. A successful on-site demonstration using a laser velocimeter system is discussed in detail. The close agreement between the LV and theoretical results demonstrates the feasibility of employing this technique in supersonic or hypersonic flow situations. Some technical experiences and considerations concerning the LV system as well as a few improvements for further development are also reported. (Modified author abstract).
Download or read book Application of Laser Velocimetry to Unsteady Flows in Large Scale High Speed Tunnels written by and published by . This book was released on 1983 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Development of a Laser Doppler Velocimetry System for Unsteady Separated Flow Research written by R. A. Kadlec and published by . This book was released on 1978 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Frank J. Seiler Research Laboratory (FJSRL) at the U.S. Air Force Academy is conducting a comprehensive experimental research program to study unsteady, separated flows and, in particular, the dynamic stall of oscillating airfoils. The aim of this study is to achieve a clearer understanding into the physical mechanisms responsible for dynamic stall and to capitalize on these unique stall features by using them to improve the turn performance and maneuverability of flight vehicles. The objective of one phase of this experimental research program has been to adapt a general purpose Laser Doppler VElocimetry (LDV) two velocity component system to dynamic stall experiments in the Subsonic Wind Tunnel at the USAFA. The preliminary design of the LDV system, its special constraints and the characterization of system signal and noise parameters are described. Results presented for the initial operation of the LDV system demonstrate its performance capabilities. It has been observed that accurate measurements in the wind tunnel environment can be achieved only when optical noise produced by scattered laser light from wind tunnel surfaces is minimized. While the LDV system configuration satisfies all constraints related to the USAFA Subsonic Wind Tunnel geometry and is capable of accurate velocity measurements in the two-dimensional flow field surrounding an airfoil, a reconfiguration of the system is suggested to improve optical alignment procedures and overall system signal-to-noise ratio. (Author).
Download or read book Development and Testing of the Virginia Tech Doppler Global Velocimeter written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new laser based flow interrogation system, capable of simultaneous measurement of planar three-component velocity data, was constructed and tested. The Virginia Tech Doppler Global Velocimeter (DGV) system was designed for use in the Virginia Tech Stability Wind Tunnel as a tool for investigating complex three-dimensional separated flow regions. The systems was designed for robustness, ease of use, and for acquisition of low uncertainty velocity data. A series of tests in the Stability Tunnel were conducted to determine the how well the new DGV system met these goals. Extensive calibration tests proved the system is capable of measuring the frequency shifts of scattered laser light, and therefore velocity. However, equipment failures and inadequate flow seed density prevented accurate velocity measurements in the separated wake region behind a 6:1 prolate spheroid. Detailed uncertainty analysis techniques demonstrated that, under the proper conditions, the system is capable of making velocity measurements with approximately +/- 2m/s uncertainty.
Download or read book Performance Test of Laser Velocimeter System for the Langley 16 foot Transonic Tunnel written by James F. Meyers and published by . This book was released on 1985 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: And investigation has been conducted in which a laser velocimeter was used to measure free-stream velocities form Mach 0.1 to 1.0 and the flow velocities along the stagnating streamline of a hemisphere-cyclinder model at Mach 0.8 and 1.0. The flow velocity was also measured at Mach 1.0 along the line 0.533 model diameters below the model. These tests determined the performance characteristics of the dedicated two-component laser velocimeter at flow velocities up to Mach 1.0 and the effects of the wind tunnel environment on the particle-generating system and on the resulting size of the generated particles. To determine these characteristics, the measured particle velocities along the stagnating streamline at the two Mach numbers were compared with the theoretically predicted gas and particle velocities calculated using a transonic potential flow method. Through this comparison the mean detectable particle size (2.1 micrometers) along with the standard deviation of the detectable particle (0.76 micrometers) was determined; thus the performance characteritics of the laser velocimeter were established. Keywords: Laser velocity; Transonic flows; Particle sizing.
Download or read book Steady Flow Field Measurements Using Laser Doppler Velocimetry written by Ricky E. Wilson and published by . This book was released on 1987 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computer-integrated LDV system utilizing a Helium-Neon laser was designed, assembled and tested for use in the study of steady flow field quantities. All system elements were integrated to include a traverse mechanism, signal processing and conditioning, computer interface and display. The system was initially calibrated utilizing a rotating wheel of known velocity. Experimental flow measurement tests of the system were conducted across a conventional free jet flow and in the Naval Postgraduate School low speed wind tunnel. The flow field velocity measurements made in the wind tunnel were verified usin an existing pressure data acquisition station and a standard pitot static probe. Keywords: Laser doppler velocimetry.
Download or read book Low Speed Wind Tunnel Testing written by Jewel B. Barlow and published by John Wiley & Sons. This book was released on 1999-02-22 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brand-new edition of the classic guide on low-speed wind tunnel testing While great advances in theoretical and computational methods have been made in recent years, low-speed wind tunnel testing remains essential for obtaining the full range of data needed to guide detailed design decisions for many practical engineering problems. This long-awaited Third Edition of William H. Rae, Jr.'s landmark reference brings together essential information on all aspects of low-speed wind tunnel design, analysis, testing, and instrumentation in one easy-to-use resource. Written by authors who are among the most respected wind tunnel engineers in the world, this edition has been updated to address current topics and applications, and includes coverage of digital electronics, new instrumentation, video and photographic methods, pressure-sensitive paint, and liquid crystal-based measurement methods. The book is organized for quick access to topics of interest, and examines basic test techniques and objectives of modeling and testing aircraft designs in low-speed wind tunnels, as well as applications to fluid motion analysis, automobiles, marine vessels, buildings, bridges, and other structures subject to wind loading. Supplemented with real-world examples throughout, Low-Speed Wind Tunnel Testing, Third Edition is an indispensable resource for aerospace engineering students and professionals, engineers and researchers in the automotive industries, wind tunnel designers, architects, and others who need to get the most from low-speed wind tunnel technology and experiments in their work.
Download or read book NASA Patent Abstracts Bibliography written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Program and published by . This book was released on 1993 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
