Experimental Investigation of Mean Flow Profile Effects on Impedance Eduction

2021 ◽  
Vol 263 (1) ◽  
pp. 5858-5868
Author(s):  
Victor Kopiev ◽  
NIkolay Ostrikov ◽  
Stanislav Denisov ◽  
MIkhail Yakovets ◽  
Maxim Ipatov
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Cross Section ◽  
Three Dimensional ◽  
Descent Method ◽  
Gradient Descent Method ◽  
Flow Profile ◽  
Mean Flow ◽  
Flow Velocity Profile ◽  
Made In

The results of experimental and computational studies of the three-dimensional mean flow velocity profile influence on the impedance eduction are presented. In order to measure the three-dimensional velocity profile, the TsAGIâ€(tm)s “Interferometer with flow†facility was upgraded so that additional holes were made in one cross section of the rectangular duct. As a result, it became possible to measure the longitudinal flow velocity in this cross section along 6 lines using a Pitot tube or a hot wire anemometer. The full three-dimensional velocity profile is determined by interpolating the values measured.Experimental results of the velocity profile for various experiment conditions are presented. Based on the numerical solution of the three-dimensional Pridmore-Brown equation by means of Finite Element Method and the gradient descent method, the problem of impedance eduction are investigated. The influence of the flow velocity profile and the form of functional on the obtained impedance values are discussed. The impedance values educted by means of this approach are compared with the impedance values obtained using two-dimensional impedance eduction methods, which didnâ€(tm)t taking into account the three-dimensional non homogeneity of the flow velocity field.

scholarly journals Turbulence Modeling Using Z-F Model and RSM for Flow Analysis in Z-SHAPE Ducts

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Mohammed Karbon ◽  
Ahmad K. Sleiti
Keyword(s):  
Steady State ◽  
Velocity Profile ◽  
Flow Velocity ◽  
Flow Separation ◽  
Experimental Results ◽  
Mean Flow ◽  
Flow Velocity Profile ◽  
The Mean ◽  
Mean Flow Velocity ◽  
Flow Reattachment

Turbulent flow in Z-shape duct configuration is investigated using Reynolds stress model (RSM) and ζ-f model and compared to experimental results. Both RSM and ζ-f models are based on steady-state RANS solutions. The focus was on regions where the RSM has over- or underpredicted the flow when compared to the experimental results and on regions where there are flow separations and high turbulence. The performance of predicting the flow reattachment length in each model is studied as well. RSM has shown the mean flow velocity profile results match reasonably well with the experiment. Advanced ζ-f turbulence model is introduced as user-defined function (UDF) code and applied to the Z-shape duct. It is found that the turbulent kinetic energy production in ζ equation is much easier to reproduce accurately. Both mean velocity gradient and local turbulent stress terms are also much easier to be resolved properly. The current research has found that not only ζ-f model takes less time to complete the simulation but also the mean flow velocity profile results are in better agreement with the experimental data than the RSM although both are coupled steady-state RANS. ζ-f model numerically resolved both the flow separation and reattachment regions better than the RSM. The current numerical results from ζ-f model are attractive and encouraging for wall-bounded flow applications where flow separation and flow reattachment are important for the flow mechanism.

Impact of Flow Velocity Profile on Ultrasonic Measurement Accuracy for Feedwater Flow in Nuclear Power Plants

2002 ◽  
Author(s):  
E. Hauser ◽  
J. Regan ◽  
H. Estrada
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Power Plants ◽  
Velocity Profiles ◽  
Nuclear Plant ◽  
Flow Profile ◽  
Practical Applications ◽  
Flow Velocity Profile ◽  
The Impact ◽  
Profile Development

This paper discusses the nature of flow velocity profiles in nuclear plant feedwater system piping, and the impact of flow profile development on flow measurement. The mechanism for flow velocity profile development is described, and the influence of upstream pipe fittings and the relative roughness of the piping inside diameter on flow development is illustrated. The paper defines fully developed flow profiles and illustrates, using several practical applications, how velocity profiles in nuclear plant feedwater piping are rarely fully developed.

scholarly journals Investigation of ultrasonic flowmeter error in distorted flow using two-peak Salami functions

2021 ◽  
Vol 7 (2) ◽  
pp. 144-151
Author(s):  
Fedir Matiko ◽  
◽  
Vitalii Roman ◽  
Halyna Matiko ◽  
Dmytro Yalinskyi
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Cross Section ◽  
Ultrasonic Flowmeter ◽  
Additional Error ◽  
Average Flow ◽  
Research Results ◽  
Pipe Cross Section ◽  
Average Flow Velocity ◽  
Flow Velocity Profile

Results of investigating the additional error of ultrasonic flowmeters caused by the distortion of the flow are presented in the article. The location coordinates of acoustic paths were calculated for their number from 1 to 6 according to the different numerical integrating methods: Gauss (Gauss-Legendre, Gauss-Jacobi), Chebyshev (equidistant location of acoustic paths), Westinghouse method, method of OWICS (Optimal Weighted Integration for Circular Sections). This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Four two-peak Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths.

Investigation of the influence of the flow structure on the accuracy of flow measurement before a hydrometric structure in an open channel

2020 ◽  
pp. 41-44
Author(s):  
Anatoly Kusher
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Water Flow ◽  
Flow Measurement ◽  
Water Discharge ◽  
Critical Depth ◽  
Flow Measurements ◽  
Study Results ◽  
Flow Velocity Profile ◽  
Upstream Flow

The reliability of water flow measurement in irrigational canals depends on the measurement method and design features of the flow-measuring structure and the upstream flow velocity profile. The flow velocity profile is a function of the channel geometry and wall roughness. The article presents the study results of the influence of the upstream flow velocity profile on the discharge measurement accuracy. For this, the physical and numerical modeling of two structures was carried out: a critical depth flume and a hydrometric overfall in a rectangular channel. According to the data of numerical simulation of the critical depth flume with a uniform and parabolic (1/7) velocity profile in the upstream channel, the values of water discharge differ very little from the experimental values in the laboratory model with a similar geometry (δ < 2 %). In contrast to the critical depth flume, a change in the velocity profile only due to an increase in the height of the bottom roughness by 3 mm causes a decrease of the overfall discharge coefficient by 4…5 %. According to the results of the numerical and physical modeling, it was found that an increase of backwater by hydrometric structure reduces the influence of the upstream flow velocity profile and increases the reliability of water flow measurements.

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