scholarly journals Applicability of the PIV system for velocity field measurement inside the ultrasonic flowmeter

2021 ◽  
Vol 345 ◽  
pp. 00024
Author(s):  
Jan Novosád ◽  
Jaroslav Pulec ◽  
Petra Dančová
Keyword(s):  
Velocity Profiles ◽  
Ultrasonic Flowmeter ◽  
Sensor Data ◽  
Experimental Setup ◽  
Area Of Interest ◽  
Image Velocimetry ◽  
The Us ◽  
Model Preparation ◽  
Future Work ◽  
Suitable Technique

Ultrasonic (US) flow meters are devices for a fluid flow measurement using the ultrasonic principle. Current research project dealing with developing the ultrasonic flowmeter with an innovative channel shape. Previously the work was aimed to the topology optimization using the CFD methods. The final prototype has to be analyzed experimentally to verify the velocity profiles in the US measurement section. The obtained velocity profiles in this region are necessary as the input for the US sensor data evaluation. A particle image velocimetry (PIV) was selected as a potentially suitable technique for the velocity profiles measurement. This paper presents the development and initial testing of a new experimental setup including the experimental track and PIV system. Several modifications were realized during the preparation of the experimental setup. Finally, measurements were performed with a simplified model and the results were evaluated in the form of velocity profiles in the area of interest. The most important results are the knowledge about the requirements on the model preparation. The future work will be aimed to the prototype of the ultrasonic flowmeter.

Experimental investigation on the momentumless wake using trailing edge blowing

2008 ◽  
Vol 222 (8) ◽  
pp. 1477-1486 ◽  
Author(s):  
Y Wu ◽  
X Zhu ◽  
Z Du
Keyword(s):  
Three Dimensional ◽  
Velocity Profiles ◽  
Axial Fan ◽  
Trailing Edge ◽  
Mean Velocity ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Velocity Spectra ◽  
Momentumless Wake ◽  
Wake Characteristics

A developed plate stator model with and without trailing edge blowing (TEB) is studied using experimental methods. Wake characteristics of flow over the stator in the three-dimensional wake regimes are studied using hot-wire anemometry (HWA) and particle image velocimetry (PIV) techniques. First, the mean velocity profiles have been measured in the wake of the stator using HWA. Four wake characteristics have been obtained through momentum thickness judgments: pure wake, weak wake, momentumless wake, and jet. These velocity profiles show some differences in momentum deficit for the four cases. Then, the velocity spectra of the pure wake and momentumless wake obtained through the HWA measurements showed that TEB can eliminate the shedding vortex of the stator. Characteristic length scales based on the wake turbulent intensity profiles showed that the momentumless wake can reduce the wake width and depth. PIV measurement is carried out to measure the flow field of the four wakes. Finally, the application of TEB approaching momentumless wake status is used on an industrial ventilation low-pressure axial fan to assess noise reduction. The results show that TEB can make the outlet of the stator uniform, reduce velocity fluctuation, destroy the vorticity structure downstream of the stator, and reduce interaction noise level of the stator and rotor.

Should Blood Lead Screening Recommendations Be Revised?

PEDIATRICS ◽  
1994 ◽  
Vol 93 (2) ◽  
pp. 201-204
Author(s):  
Birt Harvey
Keyword(s):  
Universal Screening ◽  
Human Services ◽  
Blood Lead ◽  
Consensus Conference ◽  
National Institutes Of Health ◽  
Department Of Health ◽  
Area Of Interest ◽  
The Us ◽  
Control And Prevention ◽  
Blood Lead Screening

In October 1991, the Centers for Disease Control and Prevention (CDC) recommended blood lead (BPb) screening for virtually all 1-year-old children and, preferably, for all 2-year-old children as well.1 In April 1993, the US Department of Health and Human Services distributed guidelines recommending that all newborns, regardless of race or ethnicity, be screened for sickle cell anemia.2 In June 1993, the National Institutes of Health issued a consensus conference recommendation that all infants be tested for hearing impairment within the first 3 months of life, preferably before newborns leave the hospital.3 In each instance, these screening recommendations were developed because a group of experts, after identifying a child health problem within its area of interest, believed that universal screening was indicated.

Measurement of Velocity Profiles of Laminar to Turbulent Water Flows in a Tube Using Particle Image Velocimetry

2004 ◽  
Author(s):  
Meredith R. Martin
Keyword(s):  
Reynolds Number ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Glass Tube ◽  
Reynolds Numbers ◽  
Velocity Profiles ◽  
Reynolds Number Flow ◽  
Image Velocimetry ◽  
Dye Visualization ◽  
Number Flow

The transition from laminar to turbulent in-tube flow is studied in this paper. Water flow in a glass tube with an inside diameter of 21.7 mm was investigated by two methods. First, a dye visualization test using a setup similar to the 1883 experiment of Osborne Reynolds was conducted. For the dye visualization, Reynolds numbers ranging from approximately 1000 to 3500 were tested and the transition from laminar to turbulent flow was observed between Reynolds numbers of 2500 and 3500. For the second method, a particle image velocimetry (PIV) system was used to measure the velocity profiles of flow in the same glass tube at Reynolds numbers ranging from approximately 500 to 9000. The resulting velocity profiles were compared to theoretical laminar profiles and empirical turbulent power-law profiles. Good agreement was found between the lower Reynolds number flow and the laminar profile, and between the higher Reynolds number flow and turbulent power-law profile. In between the flow appeared to be in a transition region and deviated some between the two profiles.

Joint Chilean and US mobility testing in extreme environments

2021 ◽  
Author(s):  
Michael Parker ◽  
Alex Stott ◽  
Brian Quinn ◽  
Bruce Elder ◽  
Tate Meehan ◽  
...  
Keyword(s):  
Autonomous Vehicles ◽  
Extreme Environments ◽  
Sensor Data ◽  
Unmanned Aerial Systems ◽  
Area Network ◽  
The Us ◽  
Vehicle Mobility ◽  
Data Collections ◽  
Aerial Systems ◽  
Vehicle Sensor

Vehicle mobility in cold and challenging terrains is of interest to both the US and Chilean Armies. Mobility in winter conditions is highly vehicle dependent with autonomous vehicles experiencing additional challenges over manned vehicles. They lack the ability to make informed decisions based on what they are “seeing” and instead need to rely on input from sensors on the vehicle, or from Unmanned Aerial Systems (UAS) or satellite data collections. This work focuses on onboard vehicle Controller Area Network (CAN) Bus sensors, driver input sensors, and some externally mounted sensors to assist with terrain identification and overall vehicle mobility. Analysis of winter vehicle/sensor data collected in collaboration with the Chilean Army in Lonquimay, Chile during July and August 2019 will be discussed in this report.

Blue, BlueJ, Greenfoot

2018 ◽  
pp. 42-87 ◽  
Author(s):  
Michael Kölling
Keyword(s):  
Future Development ◽  
Age Groups ◽  
Educational Systems ◽  
Diverse Group ◽  
Educational Programming ◽  
Area Of Interest ◽  
Younger Age ◽  
Programming Systems ◽  
Block Based ◽  
Future Work

Educational programming systems are booming. More systems of this kind have been published in the last few years than ever before, and interest in this area is growing. With the rise of programming as a school subject in ever-younger age groups, the importance of dedicated educational systems for programming education is increasing. In the past, professional environments were often used in programming teaching; with the shift to younger age groups, this is no longer tenable. New educational systems are currently being designed by a diverse group of developing teams, in industry, in academia, and by hobbyists. In this chapter, the authors describe their experiences with the design of three systems—Blue, BlueJ, and Greenfoot—and extract lessons that they hope may be useful for designers of future systems. The authors also discuss current developments, and suggest an area of interest where future work might be profitable for many users: the combination of aspects from block-based and text-based programming. They present their work in this area—frame-based editing—and suggest possible future development options.

User Interaction with Linked Data

2016 ◽  
Vol 7 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Dhavalkumar Thakker ◽  
Fan Yang-Turner ◽  
Dimoklis Despotakis
Keyword(s):  
Linked Data ◽  
User Study ◽  
User Interaction ◽  
Heterogeneous Data ◽  
User Studies ◽  
Sensor Data ◽  
Exploratory Search ◽  
Search Tasks ◽  
Algorithmic Support ◽  
Future Work

It is becoming increasingly popular to expose government and citywide sensor data as linked data. Linked data appears to offer a great potential for exploratory search in supporting smart city goals of helping users to learn and make sense of complex and heterogeneous data. However, there are no systematic user studies to provide an insight of how browsing through linked data can support exploratory search. This paper presents a user study that draws on methodological and empirical underpinning from relevant exploratory search studies. The authors have developed a linked data browser that provides an interface for user browsing through several datasets linked via domain ontologies. In a systematic study that is qualitative and exploratory in nature, they have been able to get an insight on central issues related to exploratory search and browsing through linked data. The study identifies obstacles and challenges related to exploratory search using linked data and draws heuristics for future improvements. The authors also report main problems experienced by users while conducting exploratory search tasks, based on which requirements for algorithmic support to address the observed issues are elicited. The approach and lessons learnt can facilitate future work in browsing of linked data, and points at further issues that have to be addressed.

Particle Image Velocimetry Measurements of Turbulent Jets Issuing From Twin Elliptic Nozzles With Various Orientations

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Ella Marie Morris ◽  
Neelakash Biswas ◽  
Seyed Sobhan Aleyasin ◽  
Mark Francis Tachie
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Symmetry Plane ◽  
Velocity Profiles ◽  
Equivalent Diameter ◽  
Linear Contraction ◽  
Turbulent Characteristics ◽  
Image Velocimetry ◽  
Nozzle Orientation ◽  
Minor Plane

Abstract The effects of nozzle orientation on the mixing and turbulent characteristics of elliptical free twin jets were studied experimentally. The experiments were conducted using modified contoured nozzles with a sharp linear contraction. The centers of the nozzle pair had a separation ratio of 5.5. Two nozzle configurations were tested, twin nozzles oriented along the minor plane (Twin_Minor) and twin nozzles oriented along the major plane (Twin_Major) and the results were compared with a single jet. In each case, the Reynolds number based on the maximum jet velocity and the equivalent diameter was 10,000. A planar particle image velocimetry (PIV) system was used to measure the velocity field in the jet symmetry plane. It was observed that the velocity decay rate is not sensitive to nozzle orientation. However, close to the jet exit, the spread rate was highest in the minor plane. In addition, contour plots of swirling strength, Reynolds shear stress and turbulent intensities revealed significant differences between the minor and major planes. Velocity profiles showed little variation close to the jet exit, while further downstream the variations between the velocity profiles were more pronounced between the major and minor planes.

Rotor Boundary Layer Response to an Impinging Wake

Volume 1 ◽  
2004 ◽  
Author(s):  
Francesco Soranna ◽  
Yi-Chih Chow ◽  
Oguz Uzol ◽  
Joseph Katz
Keyword(s):  
Boundary Layer ◽  
Guide Vane ◽  
Suction Side ◽  
Velocity Profiles ◽  
Inlet Guide Vane ◽  
Pressure Gradients ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Image Velocimetry ◽  
Entire Flow

This paper presents results of an experimental investigation on the response of a rotor boundary layer to an impinging Inlet Guide Vane (IGV) wake. High resolution two-dimensional Particle Image Velocimetry (PIV) measurements are conducted in a refractive index matched facility that provides an unobstructed view of the entire flow field. Data obtained at four different rotor phases, as the wake is chopped and passes by the rotor blade, allows us to examine the response of the rotor boundary layer to the mean flow and turbulence associated with the impinging wake. We focus on the suction side boundary layer in regions with adverse pressure gradients, from mid chord to the trailing edge. The phase-averaged velocity profiles are used for calculating the momentum and displacement thicknesses of the boundary layer, and for estimating the pressure gradients along the wall. Distributions of Reynolds stresses are also provided. The phase-averaged velocity profiles in the rotor boundary layer vary significantly with phase. During wake impingement the boundary layer becomes significantly thinner and more stable compared to other phases at the same location. Analysis of the possible causes for this trend suggests that the dominant contributors are unsteady, phase-dependent variation in pressure gradients along the wall.

scholarly journals Uncertainty comparison of velocity estimators for ultrasound flow imaging in narrow channels / Messunsicherheitsvergleich von Geschwindigkeitsschätzern der Ultraschallströmungsbildgebung in schmalen Kanälen

2019 ◽  
Vol 86 (s1) ◽  
pp. 7-11
Author(s):  
David Weik ◽  
Christian Kupsch ◽  
Richard Nauber ◽  
Lars Büttner ◽  
Jürgen Czarske
Keyword(s):  
Measurement Uncertainty ◽  
Liquid Metals ◽  
Ultrasound Image ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Flow Imaging ◽  
Lateral Velocity ◽  
Narrow Channels ◽  
Image Velocimetry ◽  
Future Work

AbstractUltrasound Imaging with a linear phased array allows measuring turbulent vector profiles in two dimension with two components (2D2C). This is interesting in narrow channels for the application in battery cells or research in magnetohydrodynamics (MHD), where the access to the opaque fluid is often restricted. There are two main velocity estimation methods applicable: the Ultrasound Doppler Velocimetry (UDV) or the Ultrasound Image Velocimetry (UIV). In this work, these methods were evaluated by their attainable measurement uncertainty for the application in narrow channels, where the acquisition of the lateral velocity component is crucial. With a calibration rig, UIV could achieve a total measurement uncertainty of 9.9% and UDV 17.6%. As UIV reaches a 44% lower measurement uncertainty, it is the preferential method to measure lateral flows in narrow channels. In future work, the calibration rig will be adapted to optimize and characterize the flow instrumentation in opaque liquid metals.

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