The properties of ripplonic polarons in a multielectron bubble in liquid helium are investigated on the basis of a path-integral variational method. We find that the two-dimensional electron gas can form deep dimples in the helium surface, or ripplopolarons, to solidify as a Wigner crystal. We derive the experimental conditions of temperature, pressure and number of electrons in the bubble for ...

This paper compares two physical mechanisms for the collapse of a bubble near a rigid wall: a traveling shock-induced collapse and a Rayleigh-like collapse due to a uniform rise of the pressure around the bubble. A multi-material compressible flow solver capable of handling material interfaces under high pressures is used to investigate these two scenarios for different levels of the driving pr...

Single bubble sonoluminescence (SBSL) is the brief flash of light emitted from a single, stable, acoustically forced bubble. In experiments, the maximum pressure amplitude with which a bubble may be forced is limited by considerations of spherical stability. The traditional linear stability analysis predicts a threshold for SBSL at a much lower pressure amplitude than experimental observations....

The radial dynamics of a single sonoluminescing bubble has been investigated in surfactant solutions. Experimental results show that an increase in the surfactant concentration leads to a decline in the oscillation amplitude and hence light emission intensity. Numerical simulations support this result, showing that under the driving pressures required to achieve single bubble sonoluminescence (...

This paper concerns a relaxation of the assumption of uniform mixture composition in the interior of sonoluminescence bubbles. Intense temperature and pressure gradients within the bubble drive relative mass diffusion which overwhelms diffusion driven by concentration gradients. This thermal and pressure diffusion results in a robust compositional inhomogeneity in the bubble which lasts several...

This paper presents measurements and model predictions of the density and size distribution of bubbles in the wakes of full scale ships, and the effects of the bubbles on acoustic propagation. The ship wake is primarily a hydrodynamic process, characterized by temporally and spatially varying flow conditions (i.e., local fluid velocity, pressure, turbulent kinetic energy and dissipation, etc.) ...

BACKGROUND Bubble CPAP is frequently used in spontaneously breathing infants with lung disease. Often bubble CPAP systems lack pressure alarms and pressure-release valves. We observed a large volume of condensate in the exhalation limb of a patient circuit and conducted a series of experiments to test the hypothesis that accumulated condensate could affect delivered pressures. METHODS An anat...

A realistic non-spherical model for bubble formation in a co-flowing liquid is presented. In the model, an interfacial element approach is applied to describe the dynamics of bubble formation. The effect of flowing liquid velocity is modeled by a combination of the bubble axis translation and liquid pressure analysis of each interfacial element. The bubble shapes during formation are predicted ...

A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas bubble in water. In order to better understand the damage caused by collapsing bubbles, the dynamics of the shock-induced and Rayleigh collapse of a bubble near a planar rigid surface and in a free field are analysed. Collapse times, bubble displacements, interfacial velocities and surface pres...

This paper evaluates the solution effects of different Rayleigh-Plesset models (R-P) for simulating the growth/collapse dynamics and thermal behaviour of homogeneous gas bubbles. The flow inputs used for the discrete cavitation bubble calculations are obtained from Reynolds-averaged Navier-Stokes simulations (RANS), performed in high-pressure nozzle holes. Parametric 1-D results are presented f...