Using an array of ultrasonic velocity transducers to improve the accuracy of large sewer mean velocity measurements

1996 ◽  
Vol 33 (1) ◽  
pp. 1-12 ◽  
Author(s):  
A. W. Hughes ◽  
I. M. Longair ◽  
R. M. Ashley ◽  
K. Kirby
Keyword(s):  
Velocity Profile ◽  
Field Testing ◽  
Doppler Velocity ◽  
Accurate Estimation ◽  
Mean Velocity ◽  
3 Dimensional ◽  
Surface Plot ◽  
Velocity Measuring ◽  
Large Flow

Portable in-sewer Doppler velocity measuring equipment has been available for a number of years. However in large sewers (typically greater than one metre diameter) the accuracy of these devices for large flow depths can be very poor. This paper describes a system, developed by the authors, that enables the determination of a velocity profile across the section of the flow in a large sewer. The velocity profile information obtained can then be used to determine a more accurate estimation of the mean velocity of flow in the large sewer. In the paper the hardware and software developed to form the Doppler Transducer Velocity Array System is discussed. Installation of the system in a large sewer and subsequent field testing of the system are also discussed, with results of the field testing included. The paper also shows how the results obtained were used to produce 3-dimensional surface plot graphs that show the variation of velocity against time across a section of the sewer flow.

Measurement and Numerical Simulation of the Velocity Profile in the Thin Film of an Impinging Water Jet

2021 ◽  
Vol 144 (3) ◽  
Author(s):  
Matthias Joppa ◽  
Mike Bermuske ◽  
Frank Rüdiger ◽  
Lars Büttner ◽  
Jochen Fröhlich ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Simulation Model ◽  
Process Optimization ◽  
Low Cost ◽  
Simulation Models ◽  
Fluid Simulation ◽  
Doppler Velocity ◽  
Measurement Technology ◽  
Mean Velocity ◽  
Validation Data

Abstract Impinging circular free-surface water jets are used in challenging cooling and cleaning tasks. In order to develop simulation models for process optimization, validation data are required, which are currently not available. Therefore, the flow field of these jets is studied for the first time with the novel laser Doppler velocity profile sensor. The mean velocity field and fluctuations are measured within the stagnation and adjacent redirection region for radial coordinates up to three times the nozzle diameter. In the examined parameter range with jet velocities up to 17 m/s and nozzle diameters up to 5.2 mm, i.e., Reynolds numbers up to 69 500, thin films of a few hundred micrometers are formed, which hinder the measurement with common optical measuring systems. Based on the measurement results, a comparatively low-cost volume of fluid simulation model is developed and validated that presumes a relaminarized film flow. The profiles measured and the simulated flow show very good agreement. In the future, the simulation model provides a basis for process optimization and the innovative measurement technology used will prospectively provide further detailed insights into other flows with high velocity gradients.

scholarly journals Advantages of modeling ABL properties to determine wind loads on structures

2018 ◽  
Vol 245 ◽  
pp. 09007 ◽  
Author(s):  
Evgenii Khrapunov ◽  
Sergei Solovev
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Velocity Profile ◽  
Experimental Tests ◽  
Wind Loads ◽  
Research Centre ◽  
Oncoming Flow ◽  
Mean Velocity ◽  
State Research

In present paper we introduce the main advantages of modeling atmospheric boundary layer (ABL) properties for determination of mean and peak wind loads on structures. Experimental tests were carried out using wind tunnel with uniform velocity profile and new Landscape Wind tunnel (LWT) of Krylov State Research Centre. General characteristics of simulated boundary layer (such as mean velocity profile and turbulence intensity profile) are presented. For wind loads measurements model of Silsoe cube in a scale of 1:15 was used. Comparison of the data obtained at both test rigs with data published in early studies is performed. New data about aerodynamic forces acting on the model in range of angles of oncoming flow are presented. Algorithm for determination of peak wind loads is discussed.

scholarly journals WIND VELOCITY PROFILE ABOVE PROGRESSIVE WATER WAVES

1968 ◽  
Vol 1 (11) ◽  
pp. 5 ◽  
Author(s):  
Omar H. Shemdin
Keyword(s):  
Velocity Profile ◽  
Water Waves ◽  
Air Velocity ◽  
Mean Velocity ◽  
Total Head ◽  
Propagating Waves ◽  
The Mean ◽  
Velocity Measuring ◽  
Wave Induced ◽  
Theoretical Results

An investigation of the air velocity profile above progressive, mechanically-generated waves was made m the wind and wave facility at Stanford University. The influence of propagating waves on the mean velocity profile was sought especially. Both the instantaneous and mean velocity profiles were obtained with the use of high response total head and static pressure probes, m conjunction with a wave height gage. Experimental evidence is presented which suggests that the air velocity field responds to the wave motion. The dependence of the mean velocity profile on wave frequency was investigated experimentally over mechanically generated waves having a constant amplitude. Also, the dependence of the mean velocity profile on wave amplitude was investigated over mechanically generated waves with a specified frequency. The theoretical results suggest that the wave influence is threefold. The first is due to the fact that a velocity-measuring instrument continuously shifts streamlines when measuring the air velocity above a perturbed water surface. The second is due to the wave-induced perturbation in the air velocity. The third is due to the interaction between the two effects just described. The results contribute towards explaining the lack of consistency in the existing data.

scholarly journals Summary-Introduction: Similarity arguments for fully developed turbulence

1960 ◽  
Vol 12 ◽  
pp. 376-384 ◽  
Author(s):  
W. V. R. Malkus
Keyword(s):  
Velocity Profile ◽  
Turbulent Flows ◽  
Mean Velocity ◽  
Shearing Flow ◽  
Fully Developed Turbulence ◽  
General Behavior ◽  
Developed Turbulence ◽  
Euler's Equations ◽  
The Mean

In the study of turbulent flows similarity arguments are used to explore the consequences of non-mechanistic assertions concerning the general behavior of the flow. For example, it is currently assumed that viscosity plays no role in the determination of the mean velocity profile of turbulent shearing flow far from a boundary. The consequences of this assumption are that the amplitude of the mean velocity will be determined by the momentum transported into such a region and that the velocity profile will be a solution to Euler's equations.

The flow of liquid in a stream from the standard turbine impeller

1979 ◽  
Vol 44 (3) ◽  
pp. 700-710 ◽  
Author(s):  
Ivan Fořt ◽  
Hans-Otto Möckel ◽  
Jan Drbohlav ◽  
Miroslav Hrach
Keyword(s):  
Reynolds Number ◽  
Kinematic Viscosity ◽  
Momentum Flux ◽  
Relative Size ◽  
Mean Velocity ◽  
Axial Profile ◽  
The Mean ◽  
Hot Film ◽  
Turbine Impeller

Profiles of the mean velocity have been analyzed in the stream streaking from the region of rotating standard six-blade disc turbine impeller. The profiles were obtained experimentally using a hot film thermoanemometer probe. The results of the analysis is the determination of the effect of relative size of the impeller and vessel and the kinematic viscosity of the charge on three parameters of the axial profile of the mean velocity in the examined stream. No significant change of the parameter of width of the examined stream and the momentum flux in the stream has been found in the range of parameters d/D ##m <0.25; 0.50> and the Reynolds number for mixing ReM ##m <2.90 . 101; 1 . 105>. However, a significant influence has been found of ReM (at negligible effect of d/D) on the size of the hypothetical source of motion - the radius of the tangential cylindrical jet - a. The proposed phenomenological model of the turbulent stream in region of turbine impeller has been found adequate for values of ReM exceeding 1.0 . 103.

scholarly journals Determination of Environmental Factors for the Implementation of the Exploitability Index in Industrial Aggregate Mining Using Multi-Criteria Analysis

2021 ◽  
Vol 10 (4) ◽  
pp. 196
Author(s):  
Julio Manuel de Luis-Ruiz ◽  
Benito Ramiro Salas-Menocal ◽  
Gema Fernández-Maroto ◽  
Rubén Pérez-Álvarez ◽  
Raúl Pereda-García
Keyword(s):  
Environmental Factors ◽  
Environmental Factor ◽  
Human Life ◽  
Accurate Estimation ◽  
Analytic Hierarchy ◽  
Main Components ◽  
Hierarchy Process ◽  
Made In

The quality of human life is linked to the exploitation of mining resources. The Exploitability Index (EI) assesses the actual possibilities to enable a mine according to several factors. The environment is one of the most constraining ones, but its analysis is made in a shallow way. This research is focused on its determination, according to a new preliminary methodology that sets the main components of the environmental impact related to the development of an exploitation of industrial minerals and its weighting according to the Analytic Hierarchy Process (AHP). It is applied to the case of the ophitic outcrops in Cantabria (Spain). Twelve components are proposed and weighted with the AHP and an algorithm that allows for assigning a normalized value for the environmental factor to each deposit. Geographic Information Systems (GISs) are applied, allowing us to map a large number of components of the environmental factors. This provides a much more accurate estimation of the environmental factor, with respect to reality, and improves the traditional methodology in a substantial way. It can be established as a methodology for mining spaces planning, but it is suitable for other contexts, and it raises developing the environmental analysis before selecting the outcrop to be exploited.

scholarly journals New Equation for Predicting Pipe Friction Coefficients Using the Statistical Based Entropy Concepts

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 611
Author(s):  
Yeon-Woong Choe ◽  
Sang-Bo Sim ◽  
Yeon-Moon Choo
Keyword(s):  
Friction Coefficient ◽  
Accurate Determination ◽  
Mean Velocity ◽  
Friction Coefficients ◽  
Flow Discharge ◽  
Comparison Results ◽  
Flow Loss ◽  
Key Variables ◽  
New Equation

In general, this new equation is significant for designing and operating a pipeline to predict flow discharge. In order to predict the flow discharge, accurate determination of the flow loss due to pipe friction is very important. However, existing pipe friction coefficient equations have difficulties in obtaining key variables or those only applicable to pipes with specific conditions. Thus, this study develops a new equation for predicting pipe friction coefficients using statistically based entropy concepts, which are currently being used in various fields. The parameters in the proposed equation can be easily obtained and are easy to estimate. Existing formulas for calculating pipe friction coefficient requires the friction head loss and Reynolds number. Unlike existing formulas, the proposed equation only requires pipe specifications, entropy value and average velocity. The developed equation can predict the friction coefficient by using the well-known entropy, the mean velocity and the pipe specifications. The comparison results with the Nikuradse’s experimental data show that the R2 and RMSE values were 0.998 and 0.000366 in smooth pipe, and 0.979 to 0.994 or 0.000399 to 0.000436 in rough pipe, and the discrepancy ratio analysis results show that the accuracy of both results in smooth and rough pipes is very close to zero. The proposed equation will enable the easier estimation of flow rates.

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