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![Figure 1-1: Working Principle [51]](profile/Matthias-Messer/publication/27524353/figure/fig1/AS:650160191332354@1532021677120/1-Working-Principle-51_Q320.jpg)
![Figure 1-2: Velocity Profile [51]](profile/Matthias-Messer/publication/27524353/figure/fig2/AS:650160191307776@1532021677138/2-Velocity-Profile-51_Q320.jpg)
![Figure 1-3: Accuracy of Pulsed Ultrasound Doppler Velocimetry [64]](profile/Matthias-Messer/publication/27524353/figure/fig3/AS:650160191332355@1532021677160/3-Accuracy-of-Pulsed-Ultrasound-Doppler-Velocimetry-64_Q320.jpg)
![Figure 2-1: Doppler Shift [52]](profile/Matthias-Messer/publication/27524353/figure/fig4/AS:650160191307777@1532021677179/1-Doppler-Shift-52_Q320.jpg)
![Figure 2-2: Ultrasonic Transducer (Emitter and Receiver) [51]](profile/Matthias-Messer/publication/27524353/figure/fig5/AS:650160191324162@1532021677259/2-Ultrasonic-Transducer-Emitter-and-Receiver-51_Q320.jpg)
Pulsed ultrasound Doppler velocimetry proved to be capable of measuring velocities accurately (relative error less than 0.5 percent). In this research, the limitations of the method are investigated when measuring: in channels with a small thickness compared to the transducer diameter, at low velocities and in the presence of a flow reversal area....
Citations
... Simulation of the ultrasonic Doppler system is carried out using the so-called meshless method in the single scattering approximation (Lester 2015, Thorne 1992, Tan 2021, Garcia 2022, Shahriari 2018, Messer 2005). The single scattering approximation is used when modeling signal scattered by particles: the secondary wave scattering is not considered, and particles do not affect each other in the first scattering act. ...
... Garcia 2022, Shahriari 2018, Messer 2005. Hereinafter the signal refers to fluid pressure variations. ...
Mud flow monitoring is essential for safe drilling and formation characterization. During coiled tubing drilling, drill cuttings are not available for direct observation and measurement. The purpose of the study is to investigate the feasibility of determining the size of the solid phase from spectra obtained by ultrasonic Doppler measurement, as well as determining the velocity of solid particles in the drilling fluid. For this purpose, numerical simulation is used with the ultrasonic measurement described using a meshless method, while the flow is simulated using a finite volume method. The developed model makes it possible to obtain spectra for various particle size distributions of the solid phase and flow characteristics, such as flow rate and viscosity. As a result, the dependence of the average signal amplitude on the concentration of solid particles in the drilling fluid was determined. Its analysis shows that the measurement in question can be used to estimate the average particle size.
... These maximum depth and velocity are inversely proportional, what is the main drawback of the technique. Details on the PUDV working principles can be found in [25]. The PUDV instrument DOP2000 (Signal ProcessingÓ) was used in the present investigation. ...
... Figure C-1: Results Acoustic Impedance Models [25] .... ...
... Particle tracking velocimetry (PTV) uses tracer particles in fluid flows. The displacement of the tracer particle is recorded in a single image over a period of time [25]. When a particle is illuminated by two bursts of light, it produces two different images on the same frame of film, and the local velocity of the fluid (Eulerian) can be approximated by measuring the distance between the images. ...
... A band-(low)pass filter is used for removing the higher frequency signal at twice the emitted frequency. The resulting signal after the band-pass filter contains the Doppler shift of the emitted signal and, thus, the velocity encountered in the medium under investigation [25]. Even though only one frequency is present at this time, a continuum of frequencies makes up the received signal. ...
The aim of this study was to characterize the interaction between a pulsed ultrasonic wave and a paper forming screen for potential development of a smart paper forming sensor to measure velocity profile of the forming jet as it impinges on the wire. To achieve this goal, a Signal-Processing DOP 2000 pulsed ultrasonic Doppler velocimeter was used to generate a pulsed ultrasonic signal. The signal was transmitted and received using four different ultrasonic transducers: a 2 MHz 10 mm, 4 MHz 5 mm, 4MHz 8 mm focused, and 8 MHz 5 mm. The ultrasonic signals were then analyzed in order to determine the ultrasonic beam echo amplitude and shape. These tests were performed with and without various paper forming screens placed between the ultrasonic transducer and an ultrasonic signal target. Two different paper forming screens were utilized to study the interaction of the ultrasonic beam with the forming screens. The tests showed that the ultrasonic signal passing through the forming screens is greatly attenuated causing a sharp decrease in echo amplitude. To overcome the attenuation of the signal, a much higher amplification of the signal was used causing an increase in the saturation region around the forming screen. This increased the minimum distance that a target had to be away from the forming screen. The closest distance from the plastic sphere to the screen over the widest range of transducer-screen-distances that produced detectable echoes was achieved with the 4 MHz 5 mm transducer. The tests showed for both screens that there is more variation in beam width when the screen is moved laterally than when it is not moved at all. They also show that even though the pores in the forming screen are very small, they seem to have a great effect on the beam width measurements of the ultrasonic transducer. David Orloff, Committee Member ; Cyrus Aidun, Committee Chair ; Timothy Patterson, Committee Member. Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005.
The vibration effect induced by acoustic pressure is one of the issues for ultrasonic Doppler velocimetry measurement in small flow channels. In this paper, the vibration effect in liquid metal lead-bismuth (PbBi) is analyzed. It is found that the vibration velocity is affected by the excitation voltage, backing layer thickness, and fluid acoustic impedance. The vibration velocity increases with excitation voltage and decreases with fluid acoustic impedance. Besides, when the thickness increases from 2 to 6 mm, the vibration velocity decreases slightly, but there are no obvious changes when the thickness is more than 6 mm. Therefore, the excitation voltage should be as low as possible, and the backing layer thickness should be more than 6 mm to minimize the vibration effect. The vibration velocity presents large fluctuation in the near field, while it decreases with the transmission distance in the far field. When the excitation voltage is 36 V, the highest vibration velocity in liquid PbBi is up to 28 mm/s in the vicinity of the transducer. Thus, it may cause relatively large deviation in the transient velocity measurement and disturb the evaluation of turbulence pulsation in small flow channels.
