Blowing big bubbles

Hamlett, Christopher; Boniface, Dolachai; Salonen, Anniina; Rio, Emmanuelle; Perkins, Connor; Clark, Alastair; Sang, Nyugen,; Fairhurst, David

doi:10.1039/d0sm01893g

“…To observe the generation of bubbles, we set up a device, in which a soap film is formed on a child's toy (with a diameter of 2.7 cm) and placed vertically in front of an airflow generator at 22 m/s. A blowing velocity, of a few tens of meters/second allows to be in a regime, where many bubbles can be created, whose size is fixed by the size of the wand [14,15].…”

Section: A Blowing Bubblesmentioning

confidence: 99%

An optimized recipe for making giant bubbles

Pasquet

¹

,

Wallon

²

,

Fusier³

et al. 2022

Self Cite

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Big bubbles are largely used in physics laboratories to study 2D turbulence, surface wavers, fundamental properties of soap systems. . . On a more artistic point of view, blowing big bubbles is part of many artistic shows. Both communities usually wan to get reasonably stable foam films. The purpose of this article is to propose the main physical ingredients allowing to identify a good recipe for making stable films and bubbles. We propose controlled experiments, to measure both the easiness to generate a bubble and its stability for different stabilizing solutions, which we choose by adding one by one the ingredients contained in an artist's recipe. The main results are that (i) the surfactant concentration must be not too high (ii) the solution must contain some long flexible polymer chains to allow an easy bubble generation and (iii) the addition of glycerol allows a better bubble stability by avoiding evaporation. We finally propose an efficient recipe, which takes into account all these considerations.

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“…Bubbles and drops are also found in other fields of engineering where they are generally dispersed in a continuous liquid phase, themselves then being qualified as the dispersed phase (firefighting foam or sparkling drinks [8]). There are many methods to make monodisperse bubbles or drops such as shearing crude emulsion to split it into droplets [9,10] or blowing on an interface [11][12][13]. One commonly used in microfluidics and called flow-focusing consists in forming bubbles (or drops) by deforming an air/liquid interface placed at the end of a tube (of square, rectangular or circular section) from a reservoir whose pressure increases [1].…”

Section: Introductionmentioning

confidence: 99%

Unstable growth of bubbles from a constriction

Grosjean

¹

,

Lorenceau

²

2023

Phys. Rev. Fluids

3

0

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Bubbles and droplets are ubiquitous in many areas of engineering, including microfluidics where they can serve as microreactors for screening of chemical reactions. They are often formed out of a constriction (a microfluidic channel or a cylindrical tube) by blowing a given volume of gas into a liquid phase. It is obviously crucial to be able to control their size, which is not always easy due to the coupling between the volume of the bubble and the gas pressure induced by the Laplace law. In this paper, we examine the size and formation dynamics of soap bubbles blown from a cylindrical tube, which is the paradigm geometry for bubble and droplet formation. To do so, one end of the tube is closed by a soap film, while the other end is connected to a large reservoir of variable volume filled with gas. To inflate the gas in the bubble, we reduce the volume of the reservoir, which mimics air inflation through the lung diaphragm or the flow-rate driven bubble formation in microfluidics geometry such as flow-focusing. As the volume of the reservoir decreases, the gas pressure increases, the soap film curves and takes the form of a spherical cap with an increasingly smaller radius of curvature. This quasi-static process continues until a critical pressure is reached for which the bubble is quasi-hemispherical. Beyond this pressure, the film undergoes a rapid topological transformation and swells very rapidly (in less than a hundred ms) until it reaches its final volume. We describe this instability in particular by showing that this unstable regime appears when a dimensionless number -whose expression we specify -reaches a critical value. Using a quasi-static model that we solve analytically, we predict the bubble growth dynamics and the final height of the bubble produced for any reservoir volume and constriction size.

show abstract

“…Bubbles and drops are also found in other fields of engineering where they are generally dispersed in a continuous liquid phase, themselves then being qualified as the dispersed phase (firefighting foam or sparkling drinks [8]). There are many methods to make monodisperse bubbles or drops such as shearing crude emulsion to split it into droplets [9,10] or blowing on an interface [11][12][13]. One commonly used in microfluidics and called flow-focusing consists in forming bubbles (or drops) by deforming an air/liquid interface placed at the end of a tube (of square, rectangular or circular section) from a reservoir whose pressure increases [1].…”

Section: Introductionmentioning

confidence: 99%

Unstable growth of bubbles from a constriction

Grosjean¹,

Lorenceau²

2022

Preprint

0

View full text Add to dashboard Cite

Bubbles and droplets are ubiquitous in many areas of engineering, including microfluidics where they can serve as microreactors for screening of chemical reactions. They are often formed out of a constriction (a microfluidic channel or a cylindrical tube) by blowing a given volume of gas into a liquid phase. It is obviously crucial to be able to control their size, which is not always easy due to the coupling between the volume of the bubble and the gas pressure induced by the Laplace law. In this paper, we examine the size and formation dynamics of soap bubbles blown from a cylindrical tube, which is the paradigm geometry for bubble and droplet formation. To do so, one end of the tube is closed by a soap film, while the other end is connected to a large reservoir of variable volume filled with gas. To inflate the gas in the bubble, we reduce the volume of the reservoir, which mimics air inflation through the lung diaphragm or the flow-rate driven bubble formation in microfluidics geometry such as flow-focusing. As the volume of the reservoir decreases, the gas pressure increases, the soap film curves and takes the form of a spherical cap with an increasingly smaller radius of curvature. This quasi-static process continues until a critical pressure is reached for which the bubble is quasi-hemispherical. Beyond this pressure, the film undergoes a rapid topological transformation and swells very rapidly (in less than a hundred ms) until it reaches its final volume. We describe this instability in particular by showing that this unstable regime appears when a dimensionless number -whose expression we specify -reaches a critical value. Using a quasi-static model that we solve analytically, we predict the bubble growth dynamics and the final height of the bubble produced for any reservoir volume and constriction size.

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Blowing big bubbles

Abstract: The radius of blown soap bubbles is very sensitive to the normalised air speed (Weber number We), growing up to ten times the wand radius in the slow speed dripping mode and reducing to just double the wand radius in the high speed jetting mode.

Cited by 5 publications

References 10 publications

An optimized recipe for making giant bubbles

An optimized recipe for making giant bubbles

Unstable growth of bubbles from a constriction

Unstable growth of bubbles from a constriction

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