Oscillations of a drop in aerodynamic levitation

Hervieu, Éric; Coutris, N.; Boichon, Christelle

doi:10.1016/s0029-5493(00)00321-6

Cited by 11 publications

(13 citation statements)

References 6 publications

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“…Apart from lense manufacture [1], this question is important for the manipulation of corrosive substances [10] or the frictionless displacement of drops [6]. Of particular interest is the maximum drop size that can be sustained, and the limit of very small flow rates.…”

Section: Introductionmentioning

confidence: 99%

Maximum size of drops levitated by an air cushion

2009

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Liquid drops can be kept from touching a plane solid surface by a gas stream entering from underneath, as it is observed for water drops on a heated plate, kept aloft by a stream of water vapor. We investigate the limit of small flow rates, for which the size of the gap between the drop and the substrate becomes very small. Above a critical drop radius no stationary drops can exist, below the critical radius two solutions coexist. However, only the solution with the smaller gap width is stable, the other is unstable. We compare to experimental data and use boundary integral simulations to show that unstable drops develop a gas "chimney" which breaks the drop in its middle.

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Section: Introductionmentioning

confidence: 99%

Maximum size of drops levitated by an air cushion

2009

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“…Precise measurement of properties of high-temperature molten material is of practical importance in many engineering fields [1][2][3]. Material properties of molten mixtures of nuclear fuel are, for instance, indispensable for evaluation of severe accident scenario of nuclear reactors [1].…”

Section: Introductionmentioning

confidence: 99%

“…Material properties of molten mixtures of nuclear fuel are, for instance, indispensable for evaluation of severe accident scenario of nuclear reactors [1]. Measurement techniques using containers are not suitable, since molten mixtures are highly reactive and corrosive, and affected by the container walls.…”

Section: Introductionmentioning

confidence: 99%

“…A levitated liquid droplet is used to measure material properties of molten material at high temperature, since the levitated droplet is not in contact with a container, and the effect of container wall is eliminated for precise measurement [4]. The levitation of liquid droplet, which is also used for container-less processing of material, is controlled by using electromagnetic [5] electrostatic [2,3,6], ultrasonic [7], or aerodynamic force [1] in the vertical direction. The levitated droplet is affected by an oscillating pressure field when the ultrasonic or acoustic levitator is used.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulation of oscillating flow field including a droplet

Watanabe¹

2013

The International Journal of Multiphysics

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“…In the last few decades, a series of studies have been performed to explore the oscillatory dynamics of liquid drops with both experimental and numerical techniques [1][2][3][4][5][6][7][8][9][10]. Many experimental studies involving axisymmetric oscillations were performed using electromagnetic levitation, acoustic levitation, electrostatic levitation and aerodynamic levitation in recent years [4,[6][7][8]11]. However, only few studies have been attempted on non-axisymmetric oscillations of an isolated drop [12][13][14].…”

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confidence: 99%

The ninth-mode sectorial oscillation of acoustically levitated drops

et al. 2011

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We report on the ninth-mode sectorial oscillation of acoustically levitated drops excited by actively modulating sound pressure. A numerical computation based on the level set method was performed to model drop shape evolution by solving an incompressible two-phase flow problem. The calculated shapes of the oscillating drop are in good agreement with experimental observations. The relationship between the oscillation frequency and parameters describing the flattened drops is studied both experimentally and numerically. The frequency of the ninth-mode sectorial oscillation decreases with increasing equatorial radius and can be well-described by a modified Rayleigh equation. Drop oscillation has been attracting considerable attention in various fields for over a century. In the last few decades, a series of studies have been performed to explore the oscillatory dynamics of liquid drops with both experimental and numerical techniques [1][2][3][4][5][6][7][8][9][10]. Many experimental studies involving axisymmetric oscillations were performed using electromagnetic levitation, acoustic levitation, electrostatic levitation and aerodynamic levitation in recent years [4,[6][7][8]11]. However, only few studies have been attempted on non-axisymmetric oscillations of an isolated drop [12][13][14]. Understanding the nature of the non-axisymmetric oscillations is desirable, not only from a scientific viewpoint but also for practical aspects related to material processing under containerless conditions. The suspension of liquid drops provides a preferable boundary condition for the investigations of various free surface phenomena. Acoustic levitation is an important containerless processing technique for in situ investigations of free-drop dynamics that require special physical environments [15][16][17][18]. It has the particular advantage of not being constrained by electromagnetic properties of the samples.Sectorial oscillations are a non-axisymmetric type of oscillation and can be characterized by either top-view or bottom-view images. Thus far, single-mode sectorial oscillations of acoustically levitated water drops have been observed up to the eighth mode. In this work, we report the ninth-mode sectorial oscillation obtained using an active modulation method. A numerical computation incorporating level set method is employed to model the observed drop shape evolution. Both experimental measurement and numerical prediction are used to investigate the relationship between the oscillation frequency and parameters describing the flattened drops. Experimental methodThe experiments are performed using a single-axis acoustic levitator, which is actuated by a piezoelectric (PZT) transducer at a frequency of 22 kHz. In the experiments, the acoustic radiation force suspends a water drop with diameter of 5 mm. To excite the levitated water drop into an oscillating state, we actively modulated the electric voltage V applied to the PZT transducer. The form of this modulation is V = V 0 (1+  cos m t)cos ac t, where  m and  ac ar...

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Oscillations of a drop in aerodynamic levitation

Cited by 11 publications

References 6 publications

Maximum size of drops levitated by an air cushion

Maximum size of drops levitated by an air cushion

Numerical simulation of oscillating flow field including a droplet

The ninth-mode sectorial oscillation of acoustically levitated drops

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