Global ETD Search
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Showing 1 to 9 of 9 for “"Doppler global velocimetry"”.
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Doppler global velocimetry measurements in a wing flow field with tip blowing
A two-component Doppler global velocimetry (DGV) system has been developed, improved, and tested. DGV is a non-intrusive optical velocity measurement technique. DGV measures the Doppler shift of the frequency of the light scattered by seed particles at a specific location. The velocity of the …
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Turbulence Statistics and Eddy Convection in Heated Supersonic Jets
… For this purpose a new instrument based on the Doppler global velocimetry technique has been developed. This instrument is capable of measuring three-component velocity vectors over ex-tended periods of time at mean data-rates of 100 kHz. As a demonstration of the applicability of the …
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Spatiotemporally-Resolved Velocimetry for the Study of Large-Scale Turbulence in Supersonic Jets
… can be correlated over several jet diameters, a velocimetry technique resolving a large region of the flow spatially and temporally is desired. This work details the development of time-resolved Doppler global velocimetry (TRDGV) for the study of large-scale turbulence in high-speed flows. The …
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Refinement and Verification of the Virginia Tech Doppler Global Velocimeter (DGV)
… a velocity measurement technique referred to as Doppler Global Velocimetry (DGV). Several hardware components in the system were modified and new hardware was added. Significant improvements were made to the procedures used in acquiring DGV data as well as the procedures used in reducing the …
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Investigation of Noise Sources in Three-Stream Jets using Turbulence Characteristics
… in three-stream nozzles. A Time-Resolved Doppler Global Velocimetry (TR-DGV) Instrument was applied to the Nozzle Acoustic Test Rig (NATR) at NASA's Aero-Acoustic Propulsion Lab (AAPL) to measure convection velocity. Particle image velocimetry (PIV) measurements provided mean velocity and …
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Advanced Instrumentation and Measurements Techniques for Near Surface Flows
… from traditional means. A new variant of Doppler global velocimetry (DGV) known as cross-correlation DGV is developed to measure boundary layer profiles on a wind turbine blade airfoil in the large scale Virginia Tech Stability Wind Tunnel. The instrument provides mean velocity vectors …
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Measurements of Scalar Convection Velocity in Heated and Unheated High-Speed Jets
… jet noise by collecting data using Time-resolved Doppler global velocimetry (TR-DGV) from regions of the jet known to produce high levels of acoustic radiation. Past experiments in studying convection velocity are reviewed based on the technique for obtaining the velocities. To add to these …
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The Effect of Thermal Non-Uniformity on Coherent Structures in Supersonic Free Jets
… for studying these structures. Time-Resolved Doppler Global Velocimetry (TR-DGV) with a sampling frequency of 50 kHz is used to collect flow velocity data that is resolved in both time and space. The experiments for data collection were performed on a heated supersonic jet at the Virginia Tech …
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Multi-Property Internal Flow Field Quantification using Molecular Filtered Rayleigh Scattering
… illumination was applied in cross-correlation Doppler global velocimetry to reduce geometric scattering contributions in image acquisition, demonstrating the removal of background scattering biases in an FRS-similar technique. For multi-property measurements, it is shown that with only an order …