Interaction between acoustically driven or laser-generated bubbles causes the bubble surfaces to deform. Dynamical equations describing the motion of two translating, nominally spherical bubbles undergoing small shape oscillations in a viscous liquid are derived using Lagrangian mechanics. Deformation of the bubble surfaces is taken into account by including quadrupole and octupole perturbations in the spherical-harmonic expansion of the boundary conditions on the bubbles. Quadratic terms in the quadrupole and octupole amplitudes are retained, and surface tension and shear viscosity are included in a consistent manner. A set of eight coupled second-order ordinary differential equations is obtained. Simulation results, obtained by numerical integration of the model equations, exhibit qualitative agreement with experimental observations by predicting the formation of liquid jets. Simulations also suggest that bubble-bubble interactions act to enhance surface mode instability.
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http://dx.doi.org/10.1121/1.3626137 | DOI Listing |
Nanoscale
December 2024
ZJUI Institute, International Campus, Zhejiang University, Haining, 314400 China.
Two-dimensional materials and their heterostructures have significant potential for future developments in materials science and optoelectronics due to their unique properties. However, their fabrication and transfer process often introduce impurities and contaminants that degrade their intrinsic qualities. To address this issue, current atomic force microscopy (AFM) probe contact mode methods provide a solution by allowing cleaning and real-time observation of the nanoscale cleaning process.
View Article and Find Full Text PDFUltrason Sonochem
December 2024
Faculty of Natural Sciences, Institute for Physics, Department Soft Matter, Otto-von-Guericke University Magdeburg, Magdeburg, 39106, Germany; Research Campus STIMULATE, University of Magdeburg, Otto-Hahn-Straße 2, Magdeburg, 39106, Germany. Electronic address:
We investigate experimentally and numerically the interaction between a spherical cavitation bubble and a wall-bounded toroidal cavitation bubble. We demonstrate that shock wave focusing following toroidal bubble initiation induces the formation of micro-jets that pierce the spherical bubble in the torus-axis direction away from the surface, strongest in the anti-phase scenario. The velocity of micro-jets is determined by the initial standoff distance of the spherical bubble from the wall and thus from the toroidal bubble, with peak jet velocities approaching 1000m/s.
View Article and Find Full Text PDFJ Acoust Soc Am
November 2024
Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom.
Both the biological effects and acoustic emissions generated by cavitation are functions of bubble dynamics. Monitoring of acoustic emissions is therefore desirable to improve treatment safety and efficacy. The relationship between the emission spectra and bubble dynamics is, however, complex.
View Article and Find Full Text PDFLangmuir
November 2024
Grupo de Medios Porosos - Facultad de Ingeniería, Universidad de Buenos Aires, Av. Paseo Colón 850, C1063ACV Ciudad Autónoma de Buenos Aires, Argentina.
The objective of this work is the study of gas microbubble dissolution in a carrier liquid. To achieve this, we will analyze, using microfluidic techniques, the formation and evolution of carbon dioxide (CO) gas microbubbles in silicone oil, monitoring the size, position, and distance between the formed bubbles as they advance through a microchannel. This work consists of two parts (Part I and Part II): in Part I, we analyze the mechanisms determining the variation in the spatial frequency of bubbles as they move through the microchannel, while Part II examines the evolution of their size and demonstrates the utility of the device for obtaining diffusion coefficients and Henry's constant for the gases used.
View Article and Find Full Text PDFUltrason Sonochem
November 2024
College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing 102249, China; Beijing Key Laboratory of Process Fluid Filtration and Separation, China University of Petroleum-Beijing, Beijing 102249, China.
The combined action of multiple particles and cavitation bubbles can severely damage hydraulic machinery. Combining the Kelvin impulse theory and the results of high-speed photography experiments, this paper researches the dynamic behaviors of a single bubble located between three equal-sized spherical particles. Non-spherical morphological evolution characteristics in the collapse stage of the bubble are described.
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