Solid exchange between the bubble wake and the emulsion phase in a gas-fluidised bed was studied both experimentally and theoretically. Measurements were made on the tracer particle concentration profile produced after a single bubble passage in a two-dimensional bed, and the solid exchange coefficients were estimated with the results of simultaneous measurements on the shape, the size and the ...

High intensity pulsed ultrasound, interacting with microbubble contrast agents, is potentially useful for drug delivery, cancer treatment, and tissue ablation, among other applications. To establish the fundamental understanding on the interaction of a microbubble (in an infinite volume of water) with an ultrasound pressure field, a numerical study is performed using the boundary element method...

It has been suggested by various authors that the 'dynamical Casimir effect' might prove responsible for the production of visible-light photons in the bubble collapse which occurs in sonoluminescence. Previously, I have argued against this point of view based on energetic considerations, in the adiabatic approximation. Those arguments have recently been strengthened by the demonstration of the...

The temperature fields inside a collapsing bubble near a plane rigid wall are investigated. We develop a numerical method based on the boundary element method combined with the finite volume method. In this method, the adaptive unstructured grids which are generated by Delaunay triangulation are used inside the largely deformable bubble to consider the heat transfer of the internal gas. We comp...

Here we report the first demonstration on droplet generation from the transformation of a single bubble in a nanofluidic channel by a laser-induced jet. A viscous two-dimensional Rayleigh-Plesset-type model is derived to describe the bubble dynamics in the nanofluidic channel, which accounts for the effect of shear stresses from the channel wall. The droplet generation (number and volume) is in...

As part of an ongoing project to develop automated tools for cryosurgery planning, the current study focuses on the development of a 3D bubble packing method. A proof-of-concept for the new method is demonstrated on five prostate models, reconstructed from ultrasound images. The new method is a modification of an established method in 2D. Ellipsoidal bubbles are packed in the volume of the pros...

An Eulerian-Lagrangian approach is developed for the simulation of turbulent bubbly flows in complex systems. The liquid phase is treated as a continuum and the Navier-Stokes equations are solved in an unstructured grid, finite volume framework for turbulent flows. The dynamics of the disperse phase is modeled in a Lagrangian frame and includes models for motion of each individual bubble, bubbl...

The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy for...

Main result. It is well known that of all surfaces surrounding an area with a given volume V, the sphere has the smallest area. This result explains, e.g., why a soap bubble tends to become a sphere. More than a hundred years ago, the Belgian physicist J. Plateaux asked a similar question: what is the least area surface enclosing two equal volumes? Physical experiments with bubbles seem to indi...

In a classical paper Plesset has determined conditions under which a bubble changing in volume maintains a spherical shape. The stability analysis was further developed by Prosperetti to include the effects of liquid viscosity on the evolving shape modes. In the present work the theory is further modified to include the changing density of the bubble contents. The latter is found to be importan...