Mechanics and physics of gas bubbles in liquids: a report on Euromech 98

Wijngaarden, L. van; Vossers, G.

doi:10.1017/s0022112078001822

Cited by 13 publications

(4 citation statements)

References 10 publications

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“…For comparison, the time dependence of bubble size under conditions of thermal growth in a superheated liquid at constant pressure, is R -t ~/2 (e.g. van Wijngaarden and Vossers 1978;Sparks 1978). When bubble growth is limited by diffusion at a constant depressurization rate the bubble size increases with time as R -t z/3 (Toramaru 1989).…”

Section: Experiments On Foamingmentioning

confidence: 99%

Deformation of foamed rhyolites under internal and external stresses: an experimental investigation

Bagdassarov

Dingwell

1993

Bull Volcanol

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Abstract. The style of magma eruption depends strongly on the character of melt degassing and foaming. Depending on the kinetics of these processes the result can be either explosive or effusive volcanism. In this study the kinetics of foaming due to the internal stresses of gas expansion of two types of obsidian have been investigated in time series experiments (2 min-24 h) followed by quenching the samples. The volumetric gas-mek ratio has been estimated through the density measurements of foamed samples.The variation of gas volume (per unit or rhyolite melt volume) with time may be described by superposition of two exponentials responsible for gas generation and gas release processes respectively. An observed difference in foaming style in this study is interpreted as the result of variations in initial contents of microlites that serve as bubble nucleation centers during devolatilization of the melts. Quantitatively the values of the gas generation rate constants (kg) are more than an order of magnitude higher in microlite-rich obsidian than in microlite-free obsidian. Possible origins of differences in the degassing style of natural magmas are discussed in the light of bubble nucleation kinetics in melts during foaming. In a complementary set of experiments the mechanical response of vesicular melt to external shear stress has been determined in a concentric cylinder viscometer. The response of vesicular melt to the pulse of shear deformation depends on the volume fraction of bubbles. The obtained response function can be qualitatively described by a Burgers body model. The experimental shear stress response function for bubble-bearing melt has an overshoot due to the strain-dependent rheology of a twophase liquid with viscously deformable inclusions.

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Section: Experiments On Foamingmentioning

confidence: 99%

Deformation of foamed rhyolites under internal and external stresses: an experimental investigation

Bagdassarov

Dingwell

1993

Bull Volcanol

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“…In this case, it would appear as though the cuboid is submerged in a mixture of bubbles and water. Thus the expressions for the pressure at the top and bottom of the cuboid should assume the forms shown in (8) and (12) respectively.…”

Section: Proofmentioning

confidence: 99%

Micro Cavitation Bubbles on the Movement of an Experimental Submarine Theory and Experiments

Mancas¹,

Sajjadi²,

Anderson³

et al. 2016

AAFM

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To further understand their nature, micro cavitation bubbles were systematically diffused around the exterior of a test body (tube) fully submerged in a water tank. The primary purpose was to assess the feasibility of applying micro cavitation as a means of depth control for underwater vehicles, mainly but not limited to submarines. Ideally, the results would indicate the use of micro cavitation as a more efficient alternative to underwater vehicle depth control than the conventional ballast tank method. The current approach utilizes the Archimedes' principle of buoyancy to alter the density of the object affected, making it less than, or greater than the density of the surrounding fluid. However, this process is too slow for underwater vehicles to react to sudden obstacles inherent in their environment. Rather than altering its internal density, this experiment aimed to investigate the response that would occur if the density of its environment was manipulated instead. In theory, and in a hydrostatic fluid, diffusing micro air bubbles from the top surface of the submarine would dilute the column of water above it with air cavities, thus lowering the density of the water. The resulting pressure differential would then cause the submarine to gain buoyancy. Conversely, diffusing micro cavities underneath the submarine would reduce its buoyancy. By this reasoning, the greater the rate of air bubbles diffused, the greater the effects would be. The independent variable in this experiment was the flow rate of diffused air, while the variable being affected was the amount of change in the buoyancy of the submarine. The results of the experiment indicated an increase in buoyancy regardless of where the micro cavities were diffused. In fact, no correlation was found between the rate at which air bubbles were diffused and the vehicle's buoyancy. Instead, it depended on the amount of air bubbles forming on the diffuser at the time, and the size of bubbles. The paper is organized as follows: in section I we introduce the experiment. In section II we present a mathematical model of a vacuous cavitation bubble where we will show how we find the radius of the bubble and its collapsing time. Also, we will calculate the time of expansion of a submarine mine prior to collapsing. In section III we will back up the theory using an experiment performed in a water tank, and we conclude with results and comments.

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“…A number of investigations of the bubble motion in liquid have been conducted in the past [2][3][4][5] due to its scientific and engineering importance. Many numerical methods have been established to simulate the motion of gas bubbles in liquid, such as VOF (volume of fluid) [6] and level set method [7].…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

Nie

Lin

Qiu

et al. 2015

Abstract and Applied Analysis

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The motion of multiple bubbles under gravity in two dimensions is numerically studied through the lattice Boltzmann method for the Eotvos number ranging from 1 to 12. Two kinds of initial arrangement are taken into account: vertical and horizontal arrangement. In both cases the effects of Eotvos number on the bubble coalescence and rising velocity are investigated. For the vertical arrangement, it has been found that the coalescence pattern is similar. The first coalescence always takes place between the two uppermost bubbles. And the last coalescence always takes place between the coalesced bubble and the bottommost bubble. For four bubbles in a horizontal arrangement, the outermost bubbles travel into the wake of the middle bubbles in all cases, which allows the bubbles to coalesce. The coalescence pattern is more complex for the case of eight bubbles, which strongly depends on the Eotvos number.

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Mechanics and physics of gas bubbles in liquids: a report on Euromech 98

Cited by 13 publications

References 10 publications

Deformation of foamed rhyolites under internal and external stresses: an experimental investigation

Deformation of foamed rhyolites under internal and external stresses: an experimental investigation

Micro Cavitation Bubbles on the Movement of an Experimental Submarine Theory and Experiments

Lattice Boltzmann Simulation of Multiple Bubbles Motion under Gravity

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