An analytical theory is developed for acoustic streaming induced by an acoustic wave field inside and outside a spherical fluid particle, which can be a liquid droplet or a gas bubble. The particle is assumed to undergo the monopole (pulsation) and the dipole (translation) oscillation modes. The dispersed phase and the carrier medium are considered to be immiscible, compressible, and viscous. The developed theory allows one to calculate the acoustic streaming both outside and inside the fluid particle. In contrast to earlier works, no restrictions are imposed on the thickness of the outer and inner viscous boundary layers with respect to the particle radius. A numerical implementation of the obtained analytical results is used to evaluate the acoustic streaming for different experimentally relevant configurations, such as an air bubble in water, a water droplet in oil, and a water droplet in air, considering both traveling and standing acoustic waves. The results show the richness of streaming pattern variations that arise in bubbles and droplets.
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http://dx.doi.org/10.1103/PhysRevE.101.013108 | DOI Listing |
Front Psychol
December 2024
The Hebrew University Business School, The Hebrew University, Jerusalem, Israel.
Introduction: In stressful times, people often listen to "coping songs" that help them reach emotional well-being goals. This paper is a first attempt to map the connection between an individual's well-being goals and their chosen coping song.
Methods: We assembled a large-scale dataset of 2,804 coping songs chosen by individuals from 11 countries during COVID-19 lockdown.
Sci Rep
January 2025
SINTEF, Department of Health Research and Department of Circulation and Medical Imaging, The Norwegian University of Science and Technology NTNU, 7491, Trondheim, Norway.
The transport of drugs into tumor cells near the center of the tumor is known to be severely hindered due to the high interstitial pressure and poor vascularization. The aim of this work is to investigate the possibility to induce acoustic streaming in a tumor. Two tumor cases (breast and abdomen) are simulated to find the acoustic streaming and temperature rise, while varying the focused ultrasound transducer radius, frequency, and power for a constant duty cycle (1%).
View Article and Find Full Text PDFComput Methods Programs Biomed
November 2024
School of Engineering, Cardiff University, Cardiff, CF24 3AA, UK.
Background And Objectives: Acoustofluidic manipulation of particles and biological cells has been widely applied in various biomedical and engineering applications, including effective separation of cancer cell, point-of-care diagnosis, and cell patterning for tissue engineering. It is often implemented within a polydimethylsiloxane (PDMS) microchannel, where standing surface acoustic waves (SSAW) are generated by sending two counter-propagating ultrasonic waves on a piezoelectric substrate.
Methods: In this paper, we develop a full cross-sectional model of the acoustofluidic device using finite element method, simulating the wave excitation on the substrate and wave propagation in both the fluid and the microchannel wall.
ACS Sens
December 2024
State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
In this work, a new method to enhance the sensing response of an ultrasonically catalyzed metal oxide gas sensor has been proposed and developed, in which pulse ultrasound is employed to enhance the redox reaction at the sensing surface. It is experimentally confirmed that with a proper pulse width, the negative effect of acoustic streaming on the ultrasonic enhancement process can be effectively suppressed. Comparing the steady responses of five target gases under the pulse and continuous ultrasound, respectively, it is found that the pulse ultrasound causes a better catalysis effect, and response enhancement (RE) by the pulse ultrasound with an optimal pulse width depends on the ultrasonic strength as well as the species and concentration of the target gas.
View Article and Find Full Text PDFSci Rep
December 2024
Acoustics Research Group, Department of Physics and Astronomy, Brigham Young University, Provo, 84602, USA.
Acoustic waves are a possible reusable method to extinguish flames. Previous studies have placed the sound source near the flame or have used standing waves to reach large enough acoustic amplitudes to extinguish it. In this study, a new method is explored: using time reversal in a room to focus transient acoustic waves to the flame to extinguish it.
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