A non-spherical model for bubble formation at an ori"ce with liquid cross-#ow has been developed. The interface element approach is applied to describe the dynamics of bubble formation. The e!ect of liquid cross-#ow on the bubble formation process is modelled by a combination of tilting of the bubble axis and liquid pressure analysis of each element on the bubble interface. Model predictions co...

We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. Bubble gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither ele...

Many studies have confirmed that cavitation in xylem is caused by air bubbles. Recently Shen et al. (Tree Physiol. 22 (2002) R655), analysed the expansion of a pre-existent bubble in xylem and one formed by air seeding. The present paper makes a further analysis of bubble expansion by the equilibrium criterion of the Helmholtz function. It has been proved that when xylem pressure P'l decreases ...

We explore the free energetics of bubble nucleation in the micellar solution subjected to a negative pressure using a density functional model of a non-ionic surfactant solution. In this two-component model, the solvent is represented by a single hard-core sphere and the surfactant is represented by two tangent hard-core spheres connected by a rigid bond. The attractive interactions between the...

Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perce...

In this paper, effects of EHD actuators on hydrodynamic behavior and heat transfer of air flow over a circular cylinder were considered. Pressure and temperature distributions around the cylinder were measured in presence of wire-plate EHD actuators. The Reynolds number based on cylinder diameter (d) were 3500, 7000. Experiments were performed for various configurations. Based on obtained resul...

All important studies on the influence of pressure on mass transfer phenomena in gas-liquid systems and reactors are reviewed critically. Points of agreement and conflict are indicated and discussed. It is concluded that: (1) the initial bubble size at a single orifice decreases with increasing pressure; (2) the gas-phase mass transfer coefficient kG is inversely proportional to the pressure to...

The main goal of this article is to study the oscillatory motion of a spherical gas bubble immersed in a Newtonian liquid subjected to a harmonic pressure excitation. We use the classical RayleighPlesset equation to study the radial motion of the bubble undergoing a forcing acoustic pressure field. The second order nonlinear ordinary differential equation that governs the bubble motion is solve...

The present study is performed to numerically analyze the growth of a vapor bubble during flow of water through a microchannel. The complete Navier– Stokes equations, along with continuity and energy equations, are solved using the SIMPLER (semi-implicit method for pressure-linked equations revised) method. The liquid–vapor interface is captured using the level set technique. The microchannel i...