When water flows through hydraulic turbomachines, the local pressure can become low enough to vaporize the water and create vapor cavities. This phenomenon is called cavitation. When the cavities collapse, shock waves and liquid jets traveling through the inclusions can erode nearby solid surfaces. The collapse of cavitation bubbles has been extensively investigated in the case of a single bubb...

Compressible large-eddy simulations of turbulent flow over a wall-mounted hump with active flow control are performedand comparedwithprevious experiments. Theflow is characterizedby the unsteady separationbefore the steep trailing edge, which naturally reattaches downstream of the hump to form an unsteady turbulent separation bubble. The lowMachnumber large-eddy simulation demonstrated a goodpr...

The effect of positive and negative pressure on the modes of oscillation of a multielectron bubble in liquid helium is calculated. Already at low pressures of the order of 10-100 mbar, these effects are found to significantly modify the frequencies of oscillation of the bubble. Stabilization of the bubble is shown to occur in the presence of a small negative pressure, which expands the bubble r...

Multibubble effects on cavitation inception are studied in detail to show that bubble-bubble interaction can change the inception process of cavitation in a variety of ways. In an effort to develop a high-power pulsed neutron source which uses a giant proton accelerator and liquid mercury, we have attempted to use microbubbles to reduce cavitation damage of the mercury vessels caused by proton-...

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 (...

INTRODUCTION Bubble formation in insulin pump giving sets is a common problem. We studied change in temperature, change in atmospheric pressure, and vibration as potential mechanisms of bubble formation. METHODS 5 Animas 2020 pumps with 2 mL cartridges and Inset II infusion systems, 5 Medtronic Paradigm pumps with 1.8 mL cartridge and Quickset and 3 Roche Accu-chek pumps with 3.15 mL cartridg...

Material deformation and pitting from cavitation bubble collapse is investigated using fluid and material dynamics and their interaction. In the fluid, a novel hybrid approach, which links a boundary element method and a compressible finite difference method, is used to capture non-spherical bubble dynamics and resulting liquid pressures efficiently and accurately. The bubble dynamics is intima...

A recent proposal by Maris[1], that single electron bubbles in helium might fission into separate, particle-like entities, does not properly take into account the failure of the adiabatic approximation when, due to tunneling, there is a long electronic time scale. The point along the fission pathway of a photoexcited p -state bubble, where the adiabatic approximation first breaks down, occurs w...