Cluster Collapse in a Cylindrical Cell: Correlating Multibubble Sonoluminescence, Acoustic Pressure, and Erosion

At present, development of manufacturer’s ultrasonic cleaning tank (UCT) to match the requirements from consumers usually relies on computer simulation based on harmonic response analysis (HRA). However, this technique can only be used with single-frequency UCT. For dual frequency, the manufacturer used information from empirical experiment alongside trial-and-error methods to develop prototypes, resulting in the UCT that may not be fully efficient. Thus, lack of such a proper calculational method to develop the dual frequency UCT was a problem that greatly impacted the manufacturers and consumers. To resolve this problem, we proposed a new model of simulation using transient dynamics analysis (TDA) which was successfully applied to develop the prototype of dual frequency UCT, 400 W, 18 L in capacity, eight horn transducers, 28 and 40 kHz frequencies for manufacturing. The TDA can indicate the acoustic pressure at all positions inside the UCT in transient states from the start to the states ready for proper cleaning. The calculation also reveals the correlation between the positions of acoustic pressure and the placement positions of transducers and frequencies. In comparison with the HRA at 28 kHz UCT, this TDA yielded the results more accurately than the HRA simulation, comparing to the experiments. Furthermore, the TDA can also be applied to the multifrequency UCTs as well. In this article, the step-by-step development of methodology was reported. Finally, this simulation can lead to the successful design of the high-performance dual frequencies UCT for the manufacturers.

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Swirl–nozzle interaction experiment: quasi-steady model-based analysis

Experiments in Fluids ◽

10.1007/s00348-021-03271-y ◽

2021 ◽

Vol 62 (8) ◽

Author(s):

Lionel Hirschberg ◽

Friedrich Bake ◽

Karsten Knobloch ◽

Angelo Rudolphi ◽

Sebastian Kruck ◽

...

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Acoustic Pressure ◽

Quantitative Information ◽

Acoustic Response ◽

Flow Measurements ◽

Flow Rate Change ◽

Interaction Experiment ◽

Swirl Stabilized Combustion

AbstractMeasurements of sound due to swirl–nozzle interaction are presented. In the experiment a swirl structure was generated by means of unsteady tangential injection into a steady swirl-free flow upstream from a choked convergent–divergent nozzle. Ingestion of swirl by the choked nozzle caused a mass-flow rate change, which resulted in a downstream-measured acoustic response. The downstream acoustic pressure was found to remain negative as long as the swirl is maintained and reflections from the open downstream pipe termination do not interfere. The amplitude of this initial acoustic response was found to be proportional to the square of the tangential mass-flow rate used to generate swirl. When the tangential injection valve was closed, the mass-flow rate through the nozzle increased, resulting in an increase of the downstream acoustic pressure. This increase in signal was compared to the prediction of an empirical quasi-steady model, constructed from steady-state flow measurements. As the opening time of the valve was varied, the signal due to swirl evacuation showed an initial overshoot with respect to quasi-steady behavior, after which it gradually decayed to quasi-steady behavior for tangential injection times long compared to the convection time in the pipe upstream of the nozzle. This demonstrates that the acoustic signal can be used to obtain quantitative information concerning the time dependence of the swirl in the system. This could be useful for understanding the dynamics of flow in engines with swirl-stabilized combustion. Graphic abstract

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A Setup for Microscopic Studies of Ultrasounds Effects on Microliters Scale Samples: Analytical, Numerical and Experimental Characterization

Pharmaceutics ◽

10.3390/pharmaceutics13060847 ◽

2021 ◽

Vol 13 (6) ◽

pp. 847

Author(s):

Florian N. Gailliègue ◽

Mindaugas Tamošiūnas ◽

Franck M. André ◽

Lluis M. Mir

Keyword(s):

Culture Medium ◽

Small Volume ◽

Acoustic Pressure ◽

Experimental Characterization ◽

Focal Distance ◽

Microscopic Studies ◽

Cell Membrane Permeabilization ◽

Ultrasonic Parameters ◽

Rigid Walls

Sonoporation is the process of cell membrane permeabilization, due to exposure to ultrasounds. There is a lack of consensus concerning the mechanisms of sonoporation: Understanding the mechanisms of sonoporation refines the choice of the ultrasonic parameters to be applied on the cells. Cells’ classical exposure systems to ultrasounds have several drawbacks, like the immersion of the cells in large volumes of liquid, the nonhomogeneous acoustic pressure in the large sample, and thus, the necessity for magnetic stirring to somehow homogenize the exposure of the cells. This article reports the development and characterization of a novel system allowing the exposure to ultrasounds of very small volumes and their observation under the microscope. The observation under a microscope imposes the exposure of cells and Giant Unilamellar Vesicles under an oblique incidence, as well as the very unusual presence of rigid walls limiting the sonicated volume. The advantages of this new setup are not only the use of a very small volume of cells culture medium/microbubbles (MB), but the presence of flat walls near the sonicated region that results in a more homogeneous ultrasonic pressure field, and thus, the control of the focal distance and the real exposure time. The setup presented here comprises the ability to survey the geometrical and dynamical aspects of the exposure of cells and MB to ultrasounds, if an ultrafast camera is used. Indeed, the setup thus fulfills all the requirements to apply ultrasounds conveniently, for accurate mechanistic experiments under an inverted fluorescence microscope, and it could have interesting applications in photoacoustic research.

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Experimental and numerical study of acoustic pressure distribution in a sonochemical reactor

Journal of Physics Conference Series ◽

10.1088/1742-6596/1809/1/012025 ◽

2021 ◽

Vol 1809 (1) ◽

pp. 012025

Author(s):

M O Kuchinskiy ◽

T P Lyubimova ◽

K A Rybkin ◽

O O Fattalov ◽

L S Klimenko

Keyword(s):

Pressure Distribution ◽

Acoustic Pressure ◽

Numerical Study

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Enhanced acoustic pressure sensors based on coherent perfect absorber-laser effect

Journal of Applied Physics ◽

10.1063/5.0041771 ◽

2021 ◽

Vol 129 (10) ◽

pp. 104902

Author(s):

Mohamed Farhat ◽

Waqas W. Ahmad ◽

Abdelkrim Khelif ◽

Khaled N. Salama ◽

Ying Wu

Keyword(s):

Acoustic Pressure ◽

Pressure Sensors ◽

Perfect Absorber ◽

Laser Effect ◽

Coherent Perfect Absorber

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Optimization of Microbubble Concentration and Acoustic Pressure for Left Ventricular High Frame Rate EchoPIV in Patients

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2021.3066082 ◽

2021 ◽

pp. 1-1

Author(s):

Jason Voorneveld ◽

Lana B.H. Keijzer ◽

Mihai Strachinaru ◽

Daniel J. Bowen ◽

Ferit O. Mutluer ◽

...

Keyword(s):

Acoustic Pressure ◽

Left Ventricular ◽

Frame Rate ◽

High Frame Rate

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Exhaust Noise Reduction by Application of Expanded Collecting System in Pneumatic Tools and Machines

Energies ◽

10.3390/en14061592 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1592

Author(s):

Dominik Gryboś ◽

Jacek S. Leszczyński ◽

Dorota Czopek ◽

Jerzy Wiciak

Keyword(s):

Experimental Data ◽

Mathematical Model ◽

Noise Reduction ◽

Sound Pressure ◽

Acoustic Pressure ◽

Pressure Level ◽

Computational Results ◽

Noise Measurements ◽

Exhaust Noise ◽

Collecting System

In this paper, we demonstrate how to reduce the noise level of expanded air from pneumatic tools. Instead of a muffler, we propose the expanded collecting system, where the air expands through the pneumatic tube and expansion collector. We have elaborated a mathematical model which illustrates the dynamics of the air flow, as well as the acoustic pressure at the end of the tube. The computational results were compared with experimental data to check the air dynamics and sound pressure. Moreover, the study presents the methodology of noise measurement generated in a pneumatic screwdriver in a quiet back room and on a window-fitting stand in a production hall. In addition, we have performed noise measurements for the pneumatic screwdriver and the pneumatic screwdriver on an industrial scale. These measurements prove the noise reduction of the pneumatic tools when the expanded collecting system is used. When the expanded collecting system was applied to the screwdriver, the measured Sound Pressure Level (SPL) decreased from 87 to 80 dB(A).

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An Overview of Acoustic Impedance Measurement Techniques and Future Prospects

Metrology ◽

10.3390/metrology1010002 ◽

2021 ◽

Vol 1 (1) ◽

pp. 17-38

Author(s):

Nandeesh Hiremath ◽

Vaibhav Kumar ◽

Nicholas Motahari ◽

Dhwanil Shukla

Keyword(s):

Acoustic Impedance ◽

Sound Pressure ◽

Acoustic Pressure ◽

Measurement Techniques ◽

Impedance Measurement ◽

Acoustic Medium ◽

Future Prospects ◽

Reverberation Chamber ◽

Field Techniques ◽

Acoustic Phenomenon

In order to progress in the area of aeroacoustics, experimental measurements are necessary. Not only are they required for engineering applications in acoustics and noise engineering, but also they are necessary for developing models of acoustic phenomenon around us. One measurement of particular importance is acoustic impedance. Acoustic Impedance is the measure of opposition of acoustical flow due to the acoustic pressure. It indicates how much sound pressure is generated by the vibration of molecules of a particular acoustic medium at a given frequency and can be a characteristic of the medium.The aim of the present paper is to give a synthetic overview of the literature on impedance measurements and to discuss the advantage and disadvantage of each measurement technique. In this work, we investigate the three main categories of impedance measurement techniques, namely reverberation chamber techniques, impedance tube techniques, and far-field techniques. Theoretical principles for each technique are provided along with a discussion on historical development and recent advancements for each technique.

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