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Showing 1 to 20 of 112 for “"LDV"”.
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LDV measurements in a Navy CPS fan
… to understand the performance of these new fans. LDV measurements of axial and tangential velocities were made in a Navy fan from upstream stations, throughout the blade row, and downstream into the stator. Data were collected two ways: (1) averaged over the entire rotor cycle and (2) averaged at …
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Experimental analysis of flow and turbulence characteristics in oscillatory boundary layers from LDV measurements
… < Rew < 9x105). A 3D laser Doppler velocimetry (LDV) system was used to measure instantaneous flow velocities with high spatial and temporal resolution, which allowed capturing flow features with great detail inside the boundary layer and even inside the viscous sublayer in some cases. A special …
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Methodology to Validate Traffic Speed Deflection Devices (TSDDs) Measurements Using Laser Doppler Vibrometers (LDV) Sensors
… non-contact multi-Laser Doppler Vibrometers (LDVs) as traceable reference sensors. The multi-LDV system, consisting of sensors similar to those used in TSDs operating within the United States, enables direct one-to-one comparisons without requiring additional data transformations. The research …
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Spectral estimates and flow characteristics from non-uniformly sampled LDV data in a turbulent junction vortex
… for randomly sampled data occurring from the LDV were evaluated under various simulated and real flow situations. The real flow situations studied were the vortex shedding flow behind a cylinder and the two-dimensional turbulent boundary layer. The spectral estimates obtained from the …
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An Experimental Study of Longitudinally Embedded Vortices in a Turbulent Boundary Layer via the Non-Invasive Comprehensive LDV Technique
This report documents the measurements of turbulence quantities resulting from vortices embedded in a zero pressure gradient turbulent boundary layer. Turbulent boundary layers are found in most flow regimes over large scale vehicles and have been studied for many years. Various systems to control …
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An Experimental Evaluation of the Experimental Spatial Dynamics Modeling (ESDM) Technique
… is the scanning laser Doppler vibrometer (LDV). A scanning LDV can measure velocity at many structure locations. An important new technique, Experimental Spatial Dynamics Modeling (ESDM), utilizes such spatially dense velocity data. ESDM models continuous, three-dimensional velocity fields …
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Towards developing a model for integrating light delivery vehicles into the rural passenger transport system in Vhembe District Municipality of South Africa
… stems from premise that Light Delivery Vehicle (LDV) passenger transport is a vital but not necessarily a safe mode in rural communities such as those in Vhembe District of Limpopo Province, South Africa. Moreover, the lack of detailed scientific data and as yet illegal status of the service …
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Vehicle Engine Classification Using of Laser Vibrometry Feature Extraction
… and remote sensor, the laser Doppler vibrometer (LDV) has been used in many different applications, such as inspection of aircrafts, bridge and structure and remote voice acquisition. However, using LDV as a vehicle surveillance device has not been feasible due to the lack of systematic …
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Development of Specialized Laser Doppler Velocimeters for High Resolution Flow Profile and Turbulence Spectral Measurements
… spatially-resolving laser-Doppler velocimetry (LDV) system for highly resolved velocity measurements in situations with limited optical access. The new instrument, a next generation version of the previously developed 'comprehensive' LDV technology, enables measurements of three components of …
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Future vehicle types and characteristics : reducing fuel consumption through shifts in vehicle segments and operating characteristics
… duty vehicle segments can impact fleet-wide LDV fuel demand. Shifts in the demand for LDV segments have occurred in recent decades, with the market share of conventional passenger cars decreasing from more than 80 percent in the early 1980s to just over half today, replaced largely by sport …
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Photodynamic Herbicide Modulators
… two major greening group of plants, i.e. the DDV/LDV and DMV/LDV groups. The following conclusions were made: (1) Cucumber, a DDV/LDV plant species, was highly susceptible to photodynamic herbicides. Protochlorophyllide was the most ubiquitous of the damage-causing anabolic photodynamic …
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Effect of Vibration of Unconsolidated Sand on the Performance of Interferometric Vibration Sensors
… are not desired. Laser Doppler vibrometers (LDV) and digital speckle pattern interferometers are studied in this thesis. The working principle of laser Doppler vibrometry and digital shearography is described. The effect of vibration of the unconsolidated sand on the performance of both …
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A Study of Compressible Turbulent Free Shear Layers Using Laser Doppler Velocimetry (Supersonic Flow, Mixing, Recirculating)
… determined by the coincident two channel LDV measurements were in agreement with the results and trends of others. Free shear layer turbulent stresses and mass flow entrainment rates were increased as a result of flow recirculation. The recirculating flow was directed towards the backstep …
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The measurement of the velocities of particles in an air-solid flow
… or inaccurate. The laser-Doppler velocity meter, LDV, was developed for measurements in single-phase flows, but it has been demonstrated by a few authors to be practical for particle velocity measurements in air-solid flows. The aim of the investigation was to find the range for which the LDV was …
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Information Processing for Biological Signals: Application to Laser Doppler Vibrometry
… activity using a Laser Doppler Vibrometer. The LDV measures surface velocity on the basis of the Doppler shift. This device is targeted on the neck overlying the carotid artery, and the proximity of the carotid to the skin results in a strong signal. Vibrations and movements from within the …
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The projected pathways and environmental impact of China's electrified passenger vehicles
… rapidly rising number of light-duty vehicles (LDVs) on the road have resulted in serious problems such as increasing CO2 emissions, energy insecurity, and air pollution. The question I examine here is how electrified vehicles (EVs) can help reduce China's energy demand and greenhouse gas (GHG) …
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Laser Doppler Vibrometry Based Remote Sensing for Active Noise Control
… developed instrument, laser Doppler vibrometer (LDV), has little been studied in the published literature in the context of sound/noise measurement and control. This thesis, therefore, investigates and develops LDV-based remote acoustic sensing techniques for ANC applications, particularly ANC …
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Hydrogen Powered Cars and Trucks: Is there a role for them in the electrified U.S. future?
… (BEV) and FCEV for both Light Duty Vehicle (LDV) and Heavy Duty Vehicle (HDV) categories. A hydrogen retail cost model is developed to provide a detailed understanding of the cost components. The fleet dynamics of Light Duty vehicles (LDV), including ICEV, BEV and FCEV, are modeled using MIT …
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Hotwire measurements of the turbulent flow into a cascade of controlled-diffusion compressor blades
… in order to verify Laser Doppler Velocimetry (LDV) data taken in earlier studies. Measurements were conducted at a Mach number of .25, a Reynolds number of 711000 and an inlet flow angle of 48 degrees. Turbulence profiles obtained in the pitch-wise direction were found to be in good agreement …
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An experimental investigation of the effects of base bleed in axisymmetric supersonic flow
… and two-component laser Doppler velocimetry (LDV). The comprehensive LDV mean velocity and turbulence measurements obtained during this study provide valuable insight into the physics of the base bleed mechanism and constitute a benchmark data set to aid analytical and computational efforts in …
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