Coalescing bubbles are known to produce a pulse of sound at the moment of coalescence, but the mechanism driving the sound production is uncertain. A candidate mechanism for the acoustic forcing is the rapid increase in the bubble volume, as the neck of air joining the two parent bubbles expands. A simple model is presented here for the volume forcing caused by the coalescence dynamics, and its...

Within bubble number limits of the varying permeability and reduced gradient bubble models, it is shown that a linear form of the saturation curve for hyperbaric exposures and a nearly constant decompression ratio for hypobaric exposures are simultaneously recovered from the phase volume constraint. Both limits are maintained within a single bubble number saturation curve. A bubble term, varyin...

A numerical scheme using Navier-Stokes computations was applied to simulate bubble dynamics in a vortex flow. A moving grid generation scheme and a Chimera grid scheme were integrated with the Navier-Stokes solver to automatically generate the appropriate grids based on the moving bubble surface. A general free surface boundary condition was implemented to describe the bubble surface motion. Th...

We implement a semi-analytic scheme for numerically computing high order polynomial approximations of the stable and unstable manifolds associated with the fixed points of the normal form for the family of quadratic volume-preserving diffeomorphisms with quadratic inverse. We use this numerical scheme to study some hyperbolic dynamics associated with an invariant structure called a vortex bubbl...

Bubbles are everyday objects and easy to make? Not so, when one is trying to generate and maintain tiny bubbles with accurately defined volumes in the nanoliter range or even smaller. This follows from the fact that the gas/liquid interface (the bubble boundary) is energetically expensive. As a consequence, this interface has a tension g and the bubble has a spherical shape (with radius R), whi...

The parameters of gas-liquid two-phase flow bubbles in field coalbed methane (CBM) wells are of great significance for analyzing coalbed methane output, judging faults in CBM wells, and developing gas drainage and extraction processes, which stimulates an urgent need for detecting bubble parameters for CBM wells in the field. However, existing bubble detectors cannot meet the requirements of th...

We introduce a robust method for computing viscous and viscoelastic two-phase bubble and drop motions. Our method utilizes a coupled level-set and volume-of-fluid technique for updating and representing the air-water interface. Our method introduces a novel approach for treating the viscous coupling terms at the air-water interface; these improvements result in improved stability for computing ...

We report on the influence of submerged bubble clouds on the remote sensing properties of water. We show that the optical effect of bubbles on radiative transfer and on the estimate of the ocean color is significant. We present a global map of the volume fraction of air in water derived from daily wind speed data. This map, together with the parameterization of the microphysical properties, sho...

We present a new model for bubbly cavitating flows. Based on volume-averaged equations, a subgrid model is added to account for a bubble, or multiple bubbles, within each computational cell. The model converges to the solution of ensembleaveraged bubbly flow equations for weak oscillations and monodisperse systems. In the other extreme, it also converges to the theoretical solution for a single...

A discrete-bubble model that predicts the rate of oxygen transfer in diffused-bubble systems is evaluated. Key inputs are the applied gas flow rate and the initial bubble size distribution. The model accounts for changes in the volume of individual bubbles due to transfer of oxygen and nitrogen (and hence changing partial pressure), variation in hydrostatic pressure, and changes in temperature....