MEASURING FLUX WITH THE IN-WELL POINT VELOCITY PROBE IN FRACTURED MEDIA

2020 ◽  
Author(s):  
Bryan Heyer ◽  
◽  
Trevor C. Osorno ◽  
Barbara A. Carrera ◽  
Chin Man W. Mok ◽  
...  
Keyword(s):  
Fractured Media ◽  
Point Velocity Probe ◽  
Point Velocity

Explosive Welding Using Underwater Shock Wave Generated by the Detonation of the Detonating Code

2011 ◽  
Vol 673 ◽  
pp. 265-270 ◽  
Author(s):  
Akihisa Mori ◽  
Li Qun Ruan ◽  
Kazumasa Shiramoto ◽  
Masahiro Fujita
Keyword(s):  
Shock Wave ◽  
Sound Velocity ◽  
Detonation Velocity ◽  
Explosive Welding ◽  
New Method ◽  
Underwater Shock Wave ◽  
Metal Plates ◽  
Experimental Parameters ◽  
Underwater Shock ◽  
Point Velocity

Detonating code is a flexible code with an explosive core. It is used to transmit the ignition of explosives with high detonation velocity in the range of 5.5 to 7 km/s. However, it is difficult to use detonating code for the explosive welding of common metals since the horizontal point velocity usually exceeds the sound velocity. Hence, in the present work, a new method using underwater shock wave generated by the detonation of detonating code was tried. The details of the experimental parameters and the results are presented. From the results it is observed that the above technique is suitable to weld thin metal plates with relatively less explosives.

Two-point similarity in temporally evolving plane wakes

2007 ◽  
Vol 577 ◽  
pp. 287-307 ◽  
Author(s):  
D. EWING ◽  
W. K. GEORGE ◽  
M. M. ROGERS ◽  
R. D. MOSER
Keyword(s):  
Large Scale ◽  
Single Point ◽  
Similarity Solutions ◽  
Similarity Analysis ◽  
Governing Equations ◽  
Large Scale Structures ◽  
Rate Dependent ◽  
Dependent Parameter ◽  
Scale Structures ◽  
Point Velocity

The governing equations for the two-point correlations of the turbulent fluctuating velocity in the temporally evolving wake were analysed to determine whether they could have equilibrium similarity solutions. It was found that these equations could have such solutions for a finite-Reynolds-number wake, where the two-point velocity correlations could be written as a product of a time-dependent scale and a function dependent only on similarity variables. It is therefore possible to collapse the two-point measures of all the scales of motions in the temporally evolving wake using a single set of similarity variables. As in an earlier single-point analysis, it was found that the governing equations for the equilibrium similarity solutions could not be reduced to a form that was independent of a growth-rate dependent parameter. Thus, there is not a single ‘universal’ solution that describes the state of the large-scale structures, so that the large-scale structures in the far field may depend on how the flow is generated.The predictions of the similarity analysis were compared to the data from two direct numerical simulations of the temporally evolving wakes examined previously. It was found that the two-point velocity spectra of these temporally evolving wakes collapsed reasonably well over the entire range of scales when they were scaled in the manner deduced from the equilibrium similarity analysis. Thus, actual flows do seem to evolve in a manner consistent with the equilibrium similarity solutions.

Estimating discharge in rivers through the combined use of dimensionless isovels and point velocity measurements

2017 ◽  
Vol 48 (3) ◽  
pp. 616-633 ◽  
Author(s):  
G. Farina ◽  
S. Alvisi ◽  
M. Franchini
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Accurate Estimation ◽  
Velocity Measurements ◽  
Combined Use ◽  
Point Velocity ◽  
New Formulation ◽  
The Relationship ◽  
River Cross Section

This paper presents a procedure for estimating discharge in a river cross-section based on the combined use of dimensionless isovels and point velocity measurements. Specifically, taking the Biot–Savart law on the magnetic field induced by an electric current in a wire as their basis as already done by other researchers, the authors propose a new formulation of the relationship characterizing the effect of the wetted perimeter on the range of velocities in a cross-section in order to take explicit account of roughness, expressed by means of Manning's coefficient. Once appropriately nondimensionalized, the isoeffect contours can be read as dimensionless isovels. Assuming in situ velocity measurements are available, discharge at a cross-section can be computed using two different methods. The proposed procedure was applied to six case studies characterized by river cross-sections which differed greatly from one another. The results show that the two methods proposed for estimating discharge lead to equivalent outcomes, and in all the cases the procedure as a whole enables a sufficiently accurate estimation of discharge, even when it is based on a limited number of velocity measurements or on the measurement of maximum surface-water velocity alone.

scholarly journals On the Use of a Single Beam Acoustic Current Profiler for Multi-Point Velocity Measurement in a Wave and Current Basin

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3881
Author(s):  
Marilou Jourdain de Thieulloy ◽  
Mairi Dorward ◽  
Chris Old ◽  
Roman Gabl ◽  
Thomas Davey ◽  
...  
Keyword(s):  
Open Water ◽  
Cost Effective ◽  
Ocean Energy ◽  
Single Beam ◽  
Test Tank ◽  
Significant Area ◽  
Current Profiler ◽  
Point Velocity ◽  
Ocean Environment ◽  
The University

Harnessing the energy of tidal currents has huge potential as a source of clean renewable energy. To do so in a reliable and cost effective way, it is critical to understand the interaction between tidal turbines, waves, and turbulent currents in the ocean. Scaled testing in a tank test provides a controlled, realistic, and highly reproducible down-scaled open ocean environment, and it is a key step in gaining this understanding. Knowledge of the hydrodynamic conditions during tests is critical and measurements at multiple locations are required to accurately characterise spatially varying flow in test tank facilities. The paper presents a laboratory technique using an acoustic velocimetry instrument, the range over-which measurements are acquired being more akin to open water applications. This enables almost simultaneous multi-point measurements of uni-directional velocity along a horizontal profile. Velocity measurements have been obtained from a horizontally mounted Single Beam Acoustic Doppler (SB-ADP) profiler deployed in the FloWave Ocean Energy Research Facility at the University of Edinburgh. These measurements have been statistically compared with point measurements obtained while using a co-located Acoustic Doppler Velocimeter (ADV). Measurements were made with both instruments under flow velocities varying from 0.6 ms−1 to 1.2 ms−1, showing that flow higher than 1 ms−1 was more suitable. Using a SB-ADP has shown the advantage of gaining 54 simultaneous measurement points of uni-directional velocity, covering a significant area with a total distance of 10 m of the test-tank, at a measurement frequency of 16 Hz. Of those measurement points, 41 were compared with co-located ADV measurements covering 8 m of the profile for a tank nominal flow velocity of 0.8 ms−1, and four distributed locations were chosen to to carry out the study at 0.6 ms−1, 1.0 ms−1, and 1.2 ms−1. The comparison with the ADV measurement showed a 2% relative bias on average.

scholarly journals Linear stochastic estimation of the coherent structures in internal combustion engine flow

2019 ◽  
Vol 21 (9) ◽  
pp. 1738-1749 ◽  
Author(s):  
Daniel Butcher ◽  
Adrian Spencer
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Stochastic Estimation ◽  
Linear Stochastic Estimation ◽  
Reference Velocity ◽  
Current Cycle ◽  
Vortex Centre ◽  
Point Velocity ◽  
Sensor Locations

A methodology for estimating the in-cylinder flow of an internal combustion engine from a number of point velocity measurements (sensors) is presented. Particle image velocimetry is used to provide reference velocity fields for the linear stochastic estimation technique to investigate the number of point measurements required to provide a representative estimation of the flow field. A systematic iterative approach is taken, with sensor locations randomly generated in each iteration to negate sensor location effects. It was found that an overall velocity distribution accuracy of at least 75% may be achieved with 7 sensors and 95% with 35 sensors, with the potential for fewer if sensor locations are optimised. The accuracy of vortex centre location predictions is typically within 2–3 mm, suggesting that the presented technique could characterise individual cycle flow fields by indicating vortex locations, swirl magnitude or tumble, for example. With this information on the current cycle, a control system may be enabled to activate in-cycle adjustment of injection and/or ignition timing, for example, to minimise emissions.

scholarly journals Estimating the Optimal Velocity Measurement Time in Rivers’ Flow Measurements: An Uncertainty Approach

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1010
Author(s):  
Robert Clasing ◽  
Enrique Muñoz
Keyword(s):  
Stability Criterion ◽  
Velocity Measurement ◽  
Measurement Time ◽  
Optimal Time ◽  
Optimal Point ◽  
Flow Measurements ◽  
Central Chile ◽  
Optimal Velocity ◽  
South Central ◽  
Point Velocity

The gauging process can be very extensive and time-consuming due to the procedures involved. Since velocity measurement time (VMT) is one of the main variables that would allow gauging times to be reduced, this study seeks to determine the optimal point VMT and, thereby, reduce the overall gauging time. An uncertainty approach based on the USGS area-velocity method and the GLUE methodology applied to eight gauging samples taken in shallow rivers located in South-central Chile was used. The average point velocity was calculated as the average of 1 to 70 randomly selected instant velocity samples (taken every one second). The time at which the uncertainty bands reached a stability criterion (according to both width and slope stability) was considered to be the optimum VMT since the variations were negligible and it does not further contribute to a less uncertain solution. Based on the results, it is concluded that the optimum point VMT is 17 s. Therefore, a point velocity measurement of 20 s is recommended as the optimal time for gauging in shallow rivers.

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