The acoustic streaming behaviour below an ultrasonic sonotrode in water was predicted by numerical simulation and validated by experimental studies. The flow was calculated by solving the transient Reynolds-Averaged Navier-Stokes equations with a source term representing ultrasonic excitation implemented from the predictions of a nonlinear acoustic model. Comparisons with the measured flow field from Particle Image Velocimetry (PIV) water experiments revealed good agreement in both velocity magnitude and direction at two power settings, supporting the validity of the model for acoustic streaming in the presence of cavitating bubbles. Turbulent features measured by PIV were also recovered by the model. The model was then applied to the technologically important area of ultrasonic treatment of liquid aluminium, to achieve the prediction of acoustic streaming for the very first time that accounts for nonlinear pressure propagation in the presence of acoustic cavitation in the melt. Simulations show a strong dependence of the acoustic streaming flow direction on the cavitating bubble volume fraction, reflecting PIV observations. This has implications for the technological use of ultrasound in liquid metal processing.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.ultsonch.2019.01.021 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany.
The emerging new generation of small-scaled acoustic microrobots is poised to expedite the adoption of microrobotics in biomedical research. Recent designs of these microrobots have enabled intricate bioinspired motions, paving the way for their real-world applications. We present a multiorifice design of air-filled spherical microrobots that convert acoustic wave energy to efficient propulsion through a resonant encapsulated microbubble.
View Article and Find Full Text PDFFront 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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!