Nitrogen stars: morphogenesis of a liquid drop

Strier, Damián E.; Duarte, Alejandro A.; Ferrari, H.; Mindlin, Gabriel B.

doi:10.1016/s0378-4371(00)00164-3

Cited by 23 publications

(22 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These oscillations can sometimes lead to a morphological bifurcation of the drop which takes the shape of a star [3,13,14,16,17]. Similar star-shaped drops have been reported in drops vertically vibrated on non-sticky surfaces, and the shape is generally attributed to a parametric instability [18].…”

Section: Introductionmentioning

confidence: 53%

See 1 more Smart Citation

Maximum size of drops levitated by an air cushion

2009

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 53%

“…A large number of studies of Leidenfrost drops have focused on the appearance of self-sustained oscillations of the drop [3,5,12,13,14,15,16,17]. These oscillations can sometimes lead to a morphological bifurcation of the drop which takes the shape of a star [3,13,14,16,17].…”

Section: Introductionmentioning

confidence: 99%

Maximum size of drops levitated by an air cushion

2009

View full text Add to dashboard Cite

show abstract

“…This section discusses some of these special dynamics. The production of vapor also generates special effects, such as self-oscillations (Leidenfrost stars) (Adachi & Takaki 1984, Snezhko et al 2008, Strier et al 2000, Takaki & Adachi 1985, Tokugawa & Takaki 1994, Wachters et al 1966, recently discussed in a short review by Brunet & Snoeijer (2011). In addition, the vapor ejection can be exploited to create self-propulsion (Linke et al 2006), which we describe in Section 3.3.…”

Section: Special Dynamicsmentioning

confidence: 98%

Leidenfrost Dynamics

Quéré

2013

Annu. Rev. Fluid Mech.

477

323

View full text Add to dashboard Cite

This review discusses how drops can levitate on a cushion of vapor when brought in contact with a hot solid. This is the so-called Leidenfrost phenomenon, a dynamical and transient effect, as vapor is injected below the liquid and pressed by the drop weight. The absence of solid/liquid contact provides unique mobility for the levitating liquid, contrasting with the usual situations in which contact lines induce adhesion and enhanced friction: hence a frictionless motion, and the possibility of bouncing after impact. All these characteristics can be combined to create devices in which selfpropulsion is obtained, using asymmetric textures on the hot solid surface.

show abstract

“…1a). Since the 1950's, a number of studies have investigated these oscillations, often with different conclusions as to their physical origin based on the complicated interplay between thermal and hydrodynamic effects in both the liquid and gas phases [13][14][15][16][17][18][19]. A simple underlying mechanism for the onset of star oscillations remains unknown.…”

mentioning

confidence: 99%

Star-shaped oscillations of Leidenfrost drops

Liétor-Santos

Burton

2017

Phys. Rev. Fluids

View full text Add to dashboard Cite

We experimentally investigate the self-sustained, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with n = 2 − 13 lobes around the drop periphery. We find that the wavelength of the oscillations depends only on the capillary length of the liquid, and is independent of the drop radius and substrate temperature. However, the number of observed modes depends sensitively on the liquid viscosity. The dominant frequency of pressure variations in the vapor layer is approximately twice the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results show that the star-shaped oscillations are driven by capillary waves of a characteristic wavelength beneath the drop, and that the waves are generated by a large shear stress at the liquid-vapor interface.PACS numbers: 47.35.Pq, 47.15.gm, 47.85.mf The Leidenfrost effect can be easily observed by placing a millimeter-scale water drop onto a sufficiently hot pan. The drop will levitate on a thermally-insulating vapor layer and survive for minutes [1][2][3][4]. For small drops, the geometry and dynamics of the vapor layer have been recently characterized [5,6]. The complex interactions between the liquid, vapor, and solid interfaces have led to a broad range of applications such as turbulent dragreduction [7], self-propulsion of drops on ratcheted surfaces [8,9], green nanofabrication [10], fuel combustion [11], and thermal control of nuclear reactors [12].Large Leidenfrost drops are well-known to form selfsustained, star-shaped oscillations (Fig. 1a). Since the 1950's, a number of studies have investigated these oscillations, often with different conclusions as to their physical origin based on the complicated interplay between thermal and hydrodynamic effects in both the liquid and gas phases [13][14][15][16][17][18][19]. A simple underlying mechanism for the onset of star oscillations remains unknown. Drops subjected to external, periodic excitations can form star oscillations with a frequency half that of the external excitation due to a parametric coupling mechanism [20,21]. However, if a parametric mechanism causes Leidenfrost stars, then the source of the periodic excitation is unclear. Recently, Bouwhuis et al. investigated the star oscillations of drops levitated by an air flow over a porous surface [22]. They showed that the onset of star oscillations occurs when the flow rate of air beneath the drop reaches a threshold, suggesting that a hydrodynamic coupling between the gas flow and liquid interface initiates the oscillations.Here we report measurements of star-shaped oscillations of six different liquids on a hot, curved surface. We observe stars with n = 2 − 13 lobes around the drop periphery. Although the number of observed modes depends on the liquid viscosity and substrate temperature, we find that the wavelength and frequency of the modes only depend on the capillary length, l c = γ/ρ l g, where γ and ρ l are the surface tension and ...

show abstract

Nitrogen stars: morphogenesis of a liquid drop

Cited by 23 publications

References 10 publications

Maximum size of drops levitated by an air cushion

Maximum size of drops levitated by an air cushion

Leidenfrost Dynamics

Star-shaped oscillations of Leidenfrost drops

Contact Info

Product

Resources

About