scholarly journals Experimental investigation of the Multipoint Ultrasonic Flowmeter

2018 ◽  
Vol 180 ◽  
pp. 02026
Author(s):  
Filipský Jakub
Keyword(s):  
Experimental Investigation ◽  
Vector Field ◽  
Velocity Field ◽  
Computer Simulations ◽  
Correlation Method ◽  
Ultrasonic Flowmeter ◽  
Ultrasonic Measurements ◽  
Parasitic Effects ◽  
Achievable Accuracy ◽  
Three Components

The Multipoint Ultrasonic Flowmeter is a vector tomographic device capable of reconstructing all three components of velocity field based solely on boundary ultrasonic measurements. Computer simulations have shown the feasibility of such a device and have been published previously. This paper describes an experimental investigation of achievable accuracy of such a method. Doubled acoustic tripoles used to obtain information of the solenoidal part of vector field show extremely short differences between the Time Of Flights (TOFs) of individual sensors and are therefore sensitive to parasitic effects of TOF measurements. Sampling at 40MHz and correlation method is used to measure the TOF.

Estimation Errors of Component Spectra Estimated by Means of the Concentration-Spectrum Correlation: Part II

1989 ◽  
Vol 43 (5) ◽  
pp. 855-860 ◽  
Author(s):  
Jun Uozumi ◽  
Toshimitsu Asakura
Keyword(s):  
Theoretical Analysis ◽  
Computer Simulations ◽  
Estimation Error ◽  
Correlation Method ◽  
Statistical Technique ◽  
Weighting Factor ◽  
Estimation Errors ◽  
True Discrimination ◽  
Spectrum Correlation ◽  
Nonparametric Statistical

Estimation errors accompanying component spectra calculated by means of the concentration-spectrum correlation method are investigated by theoretical analysis and computer simulations. Discussion is concentrated on a modified version of the method, which operates under the constraint that the sum of all the component concentrations in a sample is unity. In an agreement similar to that for the basic method, which was treated in an earlier paper [Appl. Spectrosc. 43, 74 (1989)], the estimation error consists of a superposition of other component spectra, each multiplied by a weighting factor. In this case, however, the weighting factor is a function of five sample statistics: the averages and the standard deviations of the concentrations of both the objective and the interfering components, and the correlation coefficient of these two components. It is shown again that the nonparametric statistical technique called a bootstrap is useful as a tool of false-true discrimination of the peaks in the estimated spectra.

scholarly journals Experimental investigation of longitudinal space–time correlations of the velocity field in turbulent Rayleigh–Bénard convection

2011 ◽  
Vol 683 ◽  
pp. 94-111 ◽  
Author(s):  
Quan Zhou ◽  
Chun-Mei Li ◽  
Zhi-Ming Lu ◽  
Yu-Lu Liu
Keyword(s):  
Experimental Investigation ◽  
Velocity Field ◽  
Space Time ◽  
Turbulent Shear ◽  
Convection Cell ◽  
Mean Velocity ◽  
Bénard Convection ◽  
Benard Convection ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

AbstractWe report an experimental investigation of the longitudinal space–time cross-correlation function of the velocity field, $C(r, \tau )$, in a cylindrical turbulent Rayleigh–Bénard convection cell using the particle image velocimetry (PIV) technique. We show that while Taylor’s frozen-flow hypothesis does not hold in turbulent thermal convection, the recent elliptic model advanced for turbulent shear flows (He & Zhang, Phys. Rev. E, vol. 73, 055303) is valid for the present velocity field for all over the cell, i.e. the isocorrelation contours of the measured $C(r, \tau )$ have an elliptical curve shape and hence $C(r, \tau )$ can be related to $C({r}_{E} , 0)$ via ${ r}_{E}^{2} = (r\ensuremath{-} U\tau )^{2} + {V}^{2} {\tau }^{2} $ with $U$ and $V$ being two characteristic velocities. We further show that the fitted $U$ is proportional to the mean velocity of the flow, but the values of $V$ are larger than the theoretical predictions. Specifically, we focus on two representative regions in the cell: the region near the cell sidewall and the cell’s central region. It is found that $U$ and $V$ are approximately the same near the sidewall, while $U\simeq 0$ at the cell centre.

Experimental investigation of the correlation method for detecting radiation contamination of moving objects

Atomic Energy ◽  
1996 ◽  
Vol 81 (1) ◽  
pp. 475-478
Author(s):  
A. F. Serov ◽  
S. V. Ursul ◽  
K. M. Kirillov ◽  
I. V. Padyukov ◽  
S. V. Krotov
Keyword(s):  
Experimental Investigation ◽  
Moving Objects ◽  
Correlation Method ◽  
Radiation Contamination

scholarly journals 380 Assessment of 2D velocity field using contrast echo. Comparison of Weiner filtering and cross-correlation method

2006 ◽  
Vol 7 ◽  
pp. S46-S47
Author(s):  
S DUBOIS ◽  
N BENARD ◽  
L CHRISTIAENS ◽  
P BLOUIN ◽  
R PERRAULT ◽  
...  
Keyword(s):  
Velocity Field ◽  
Cross Correlation ◽  
Correlation Method

scholarly journals VELOCITY FIELD IN A STEADY BREAKER

1980 ◽  
Vol 1 (17) ◽  
pp. 30
Author(s):  
J.A. Battjes ◽  
T. Sakai
Keyword(s):  
Experimental Investigation ◽  
Velocity Field ◽  
Flow Field ◽  
Turbulent Flow ◽  
Turbulent Wake ◽  
Laser Doppler ◽  
Reynolds Stresses ◽  
Doppler System ◽  
Steady Current ◽  
Turbulent Flow Field

An experimental investigation is described of the velocity field in a steady, spilling-type breaker, generated on a steady current by a submerged hydrofoil. Velocities have been measured with a laser-doppler system, and analysed with respect to mean and rms-values as well as Reynolds stresses. The results indicate that the turbulent flow field downstream of the initiation of the separation at the surface resembles that in a turbulent wake.

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