Gas bubbles in a Hele-Shaw cell manipulated by a light beam

Bezuglyi, B. A.; Иванова, Н. Л.

doi:10.1134/1.1519020

Cited by 11 publications

(11 citation statements)

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“…This phenomenon has long been known as the Marangoni or thermocapillary effect. 1,2 Fluid manipulation mediated by this Marangoni effect has been investigated numerically 3-6 and experimentally [7][8][9][10][11][12][13] and its potential for microfluidic control has been shown. Especially, a small bubble of the order of 10 lm was shown to be capable of developing a jet like Marangoni flow with a high velocity of more than 100 mm/s using a thin wire heater of 0.1 mm diameter.…”

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confidence: 99%

Photothermally controlled Marangoni flow around a micro bubble

Namura

Nakajima

Kimura

et al. 2015

Applied Physics Letters

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We have experimentally investigated the control of Marangoni flow around a micro bubble using photothermal conversion. Using a focused laser spot acting as a highly localized heat source on Au nanoparticles/dielectric/Ag mirror thin film enables us to create a micro bubble and to control the temperature gradient around the bubble at a micrometer scale. When we irradiate the laser next to the bubble, a strong main flow towards the bubble and two symmetric rotation flows on either side of it develop. The shape of this rotation flow shows a significant transformation depending on the relative position of the bubble and the laser spot. Using this controllable rotation flow, we have demonstrated sorting of the polystyrene spheres with diameters of 2 lm and 0.75 lm according to their size. V

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confidence: 99%

Photothermally controlled Marangoni flow around a micro bubble

Namura

Nakajima

Kimura

et al. 2015

Applied Physics Letters

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“…It is the aim of the present paper to consider the generalization of the well-investigated Hele-Shaw flow problem to the case of nonconstant surface tension coefficient (or surface energy density). While experiments on such situations have been reported in the literature (e.g., [3,12]), theoretical investigations of this seem to be lacking. A first step in this direction has been made in [10] where shorttime solvability was proved for a Hele-Shaw problem with nonconstant surface tension coefficient and so-called kinetic undercooling.…”

Section: Ams Subject Classifications 35r35 76b07mentioning

confidence: 99%

“…While experiments on such situations have been reported in the literature (e.g., [3,12]), theoretical investigations of this seem to be lacking. A first step in this direction has been made in [10] where shorttime solvability was proved for a Hele-Shaw problem with nonconstant surface tension coefficient and so-called kinetic undercooling.…”

Section: Introductionmentioning

confidence: 99%

On a Hele–Shaw Type Domain Evolution with Convected Surface Energy Density: The Third‐Order Problem

Günther¹,

Prokert²

2006

SIAM J. Math. Anal.

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Abstract. We investigate a moving boundary problem with a gradient flow structure which generalizes Hele-Shaw flow driven solely by surface tension to the case of nonconstant surface tension coefficient taken along with the liquid particles at boundary. The resulting evolution problem is first order in time, contains a third-order nonlinear pseudodifferential operator and is degenerate parabolic. Well-posedness of this problem in Sobolev scales is proved. The main tool is the construction of a variable symmetric bilinear form so that the third-order operator is semibounded with respect to it. Moreover, we show global existence and convergence to an equilibrium for solutions near trivial equilibria (balls with constant surface tension coefficient). Finally, numerical examples in 2D and 3D are given.Key words. free boundary motion, degenerate nonlocal parabolic evolution AMS subject classifications. 35R35, 76B07DOI. 10.1137/0506269951. Introduction. It is the aim of the present paper to consider the generalization of the well-investigated Hele-Shaw flow problem to the case of nonconstant surface tension coefficient (or surface energy density). While experiments on such situations have been reported in the literature (e.g., [3,12]), theoretical investigations of this seem to be lacking. A first step in this direction has been made in [10] where shorttime solvability was proved for a Hele-Shaw problem with nonconstant surface tension coefficient and so-called kinetic undercooling. Here we discuss the problem without this regularization, using again the simple assumption that the surface energy density is convectively transported along the moving boundary.This leads to the following moving boundary problem: For a given bounded domain Ω(0) ⊂ R m and a given nonnegative function γ 0 defined on ∂Ω(0) one looks for a family of C 2 -domains Ω(t) ⊆ R m , t > 0 and functions ϕ(·, t) ∈ C 2 Ω(t) ,

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“…The bubble motion mechanism is due to the action of thermocapillary forces on its surface. These forces results from a decrease in the liquid surface tension [σ = σ 0 + σ T (T − T 0 )] near the bubble due to local heating by the light beam [12].…”

Section: Experimental Procedure a Diagram Of The Setup Is Shown Inmentioning

confidence: 99%

“…Later, Bezuglyi and Ivanova [12] reported results from studies of bubble motion behind a light beam and for the first time gave a qualitative explanation of the motion mechanism based on the action of localized thermocapillary liquid vortices induced by the light beam at the lateral surface of the bubble.…”

Section: Introduction Bubble Motion In a Hele-shaw Cell (H/dmentioning

confidence: 97%

Thermocapillary Vortices Induced by a Light Beam near a Bubble Surface in a Hele-Shaw Cell

Иванова

Bezuglyi

2005

J Appl Mech Tech Phys

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This paper studies thermocapillary vortices induced by local heating of a bubble surface in a HeleShaw cell by a light beam. It is found that the vortex rotation frequency and its depth depend on the distance from the light-beam projection onto the layer to the bubble boundary. The surface velocity of the thermocapillary flow is calculated using the balance of the near-surface and return flows of the thermocapillary vortex and the equality of capillary and dynamic pressures. It is shown that a decrease in the surface velocity and the vortex rotation frequency with increase in the distance from the light beam to the bubble surface is due to a decrease in the temperature gradient between the illuminated and cold poles of the bubble. Introduction. Bubble motion in a Hele-Shaw cell (h/D1, where D is the bubble diameter and h is the cell spacing) has been extensively studied both theoretically and experimentally [1][2][3][4]. Recently, interest in this problem has increased because of the need to develop methods for controlling liquids and bubbles in microscale bubble pumps, biochips, etc. [5,6]. However, for duct flows, the examined mechanisms of bubble motion due to mechanically produced pressure gradients [1][2][3] or the buoyancy forces arising from the cell inclination [4] are inefficient or do not operate altogether. For example, for ethanol drops (ρ = 800 kg/m 3 and σ = 22.8 · 10 −3 N/m [7]) moving at a velocity of 1 cm/sec inside a microchannel with a cross-sectional size of 100 µm, the Bond number and the capillary number have orders of magnitude Bo ≈ 10 −3 and Ca ≈ 10 −4 , respectively. That small values indicate that in the problems considered, capillary forces dominate over gravitational and viscous forces. The migration of bubbles under the action of thermocapillary forces was first demonstrated by Young et al. [8], who studied bubble motion under the action of a vertical temperature gradient ∇T opposite to the buoyancy force. Mazouchi and Homsy [9] and Lajeunesse and Homsy [10] performed experimental and theoretical studies of bubble motion in polygonal microchannels under the action of thermocapillary forces related to a longitudinal temperature gradient [9, 10].The possibility of controlling bubbles in a Hele-Shaw cell by means of a local temperature gradient induced by the thermal action of a light beam was first shown by Bezuglyi [11]. Later, Bezuglyi and Ivanova [12] reported results from studies of bubble motion behind a light beam and for the first time gave a qualitative explanation of the motion mechanism based on the action of localized thermocapillary liquid vortices induced by the light beam at the lateral surface of the bubble.In the present work, an attempt was undertaken to obtain quantitative information on the size of thermocapillary vortices induced by the thermal action of light, the frequency of their rotation and flow velocity on the bubble surface.

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Gas bubbles in a Hele-Shaw cell manipulated by a light beam

Cited by 11 publications

References 4 publications

Photothermally controlled Marangoni flow around a micro bubble

Photothermally controlled Marangoni flow around a micro bubble

On a Hele–Shaw Type Domain Evolution with Convected Surface Energy Density: The Third‐Order Problem

Thermocapillary Vortices Induced by a Light Beam near a Bubble Surface in a Hele-Shaw Cell

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