Correlation Method for Measuring Reflection Coefficients of Sharp-Edged Orifices for small-Amplitude Pressure Waves

1973 ◽  
Vol 15 (5) ◽  
pp. 321-325 ◽  
Author(s):  
M. A. Ali ◽  
E. W. Reed ◽  
K. F. Gill
Keyword(s):  
Pressure Pulse ◽  
Binary Sequence ◽  
Correlation Method ◽  
Reflection Coefficients ◽  
Correlation Technique ◽  
Pressure Waves ◽  
One Dimensional ◽  
Pulse Testing ◽  
End Conditions ◽  
Pressure Wave Amplitude

A correlation technique using pseudo-random binary-sequence pressure-pulse testing is used to measure reflection coefficients of sharp edged orifices at the end of a duct. Within the range of the incident pressure-wave amplitude investigated in this paper it is believed that no other experimental means has yet been devised. A simple formula is derived from one-dimensional flow theory which gives values showing close agreement with the experimental results. End conditions for non-reflection are established to create an analogy to the hypothetical ‘infinite pipe’.

The Effect of Mass Flow Rate on the Reflection Behaviour of Small-Amplitude Pressure Waves from Duct Terminations

1978 ◽  
Vol 20 (4) ◽  
pp. 229-235 ◽  
Author(s):  
M. A. Ali ◽  
K. F. Gill ◽  
B. W. Imrie
Keyword(s):  
Reflection Coefficient ◽  
Steady Flow ◽  
Mass Flow ◽  
Small Amplitude ◽  
Binary Sequence ◽  
Low Flow ◽  
Correlation Technique ◽  
Pressure Waves ◽  
Flow Number ◽  
Wide Range

This paper describes an investigation of the reflection characteristics of small-amplitude pressure waves in the presence of steady flow in a duct. A correlation technique employing pseudo-random binary-sequence (p.r.b.s.) pulses is introduced. A theoretical model of the process is presented together with considerations of correlation analysis. The results show agreement between the experimental results and the model; they further indicate that, in the presence of a steady flow component, there is a significant effect on the reflection behaviour of plane pressure waves for a reduction in the area terminating a duct. The experimental technique is effective at very low flow velocities (Mach number = 0·02, Reynolds number = 30 times 103) and establishes a linear relationship between a reflection coefficient and a non-dimensional mass flow number. A reflection coefficient of flow is introduced as an appropriate parameter for such conditions. The procedure could be applied to a wide range of industrial processes to determine flow coefficients of duct elements in situ, to optimize flow processes and to locate leakage flows.

Pressure Pulse Testing Method for Caprock Characterization

2018 ◽  
Author(s):  
Mojtaba Mosaheb ◽  
Mehdi Zeidouni ◽  
Mahmood Shakiba
Keyword(s):  
Pressure Pulse ◽  
Testing Method ◽  
Pulse Testing

Possible Detection of Multiple Blockages Using Transients

2001 ◽  
Author(s):  
Michael A. Adewumi ◽  
E. S. Eltohami ◽  
A. Solaja
Keyword(s):  
Single Phase ◽  
Pressure Pulse ◽  
Eulerian Model ◽  
One Dimensional ◽  
Internal Configuration

Abstract This work explores the possibility of utilizing the interaction between a pressure pulse propagating in a pipe with the blockages therein, as a means of blockage detection and characterization. Whereas an earlier work focused on a single blockage, the present work attempts to extend the strategy to multiple blockages. A one-dimensional isothermal non-compositional single-phase Eulerian model was used to describe the propagation of a pressure pulse through a pipe with multiple blockages. Pressure variations at the inlet caused by reflections of the propagating transient are monitored and analyzed. This analysis is used to make deductions about the internal configuration of the pipe. The results demonstrate that the technique is feasible and that accurate characterization of multiple blockages is possible.

Phase Correlation Processing for DPIV Measurements: Part II — Spectral Domain Analysis

2007 ◽  
Author(s):  
Adric C. Eckstein ◽  
John J. Charonko ◽  
Pavlos P. Vlachos
Keyword(s):  
Least Squares ◽  
Particle Image ◽  
Energy Content ◽  
Weighted Least Squares ◽  
Correlation Method ◽  
Phase Correlation ◽  
Spectral Domain ◽  
Correlation Technique ◽  
Correlation Processing ◽  
Robust Least Squares

A novel Digital Particle Image Velocimetry (DPIV) correlation method is introduced which estimates the displacement using the phase content within the Fourier based cross-correlation. The use of weighted least squares and robust least squares estimation is introduced in order to improve the linear phase estimation of this technique. Spectral filters are constructed using the energy content of PIV images to define weighting functions for the dominant singular vector regressions. This performance of this technique is measured using Monte Carlo simulations of DPIV images. The resulting error analysis demonstrates substantially reduced errors for higher particle-image diameters for images containing low amounts of noise. For high noise images, the reduction in bias and RMS errors is not as drastic due to limitations of extracting the phase information. However, this correlation technique is able to eliminate peak-locking errors, shown to be a substantial source of error in noisy images, by directly extracting the displacement information in the spectral domain.

Sign in / Sign up

Export Citation Format

Share Document