Detection of liquid bridge contours and its applications

Cabezas, M.G.; Montanero, J. M.; Acero, Francisco Javier; Jaramillo, M.A.; Fernández, Juan A.

doi:10.1088/0957-0233/13/6/302

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…18 On the other hand, liquid bridges are also used as accelerometers. 19,20 With respect to the former applications, it is noted that the present work is limited to Newtonian liquids only.…”

Section: Introductionmentioning

confidence: 99%

Dynamic stretching of a planar liquid bridge

Mehring

Sirignano

2004

Physics of Fluids

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A thin incompressible viscous planar free liquid film in a void and under zero gravity is analyzed by means of a reduced-dimension ͑lubrication͒ approach. Linear analysis focuses on films with harmonic modulations in the axial film velocity enforced at the ends of the planar bridge. Effects of changes in the problem parameters on the overall distortion characteristics of the film are discussed. Nonlinear film distortion and break-up are investigated for the case of temporally increasing velocity at the end of the film resulting in continuous film stretching eventually leading to film rupture. Implementation of the employed numerical model is validated for the linear limit by comparison with the analytical linear solutions and for harmonically modulated film-end velocities. Within the nonlinear analysis of the continuously stretched film bridge, several distinct film topologies are identified depending on liquid Weber number and Reynolds number, i.e., the magnitude of the stretching rate ͑end velocity͒ compared to signal propagation rates through the liquid via capillary waves and viscous action. That is, the Weber number is the square of the ratio of stretching rate to capillary wave velocity while the Reynolds number is the ratio of stretching rate to the characteristic viscous velocity. Here, film topology is typically characterized by three distinct regions, i.e., a film wedge forming at the pulling end͑s͒, the film center region and a transition region. The size and shape of these regions greatly depend on the particular case under investigation. Film distortion characteristics observed for continuously compressed planar films conform with observations made by other authors for the similar case of contracting free liquid films.

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Section: Introductionmentioning

confidence: 99%

Dynamic stretching of a planar liquid bridge

Mehring

Sirignano

2004

Physics of Fluids

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“…This shape or spatial profile strongly depends on the physico-chemical properties of the liquid phase. The analysis of spatial profiles in liquid bridges can be used, for example, either as an accelerometer for steady accelerations or as a tensiometer [1], while in FZs related to crystal growth it might be used as a control parameter to prevent problems associated to composition, stress and regularity in diameter of grown crystals.…”

Section: Introductionmentioning

confidence: 99%

Study of floating zone profiles in materials grown by the laser‐heated pedestal growth technique under isostatic atmosphere

Ardila¹,

Cofré²,

Barbosa³

et al. 2004

Cryst. Res. Technol.

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The analysis of the melt profile in floating zone techniques has been made in the past years by raising differential equations in terms of Cartesian coordinates and numerically looking for its solution. Although this method permits to establish quite good approximations to the real melt profile, the solutions are deficient in the prediction of new information that can be related to the thermophysical properties of most materials. We investigated the applicability of a different approach that starting from a novel differential equation permits its fitting to the profile of a real situation and also the determination of some important growth parameters like the range of shape stability. Results concerning melt profiles of materials grown under controlled atmosphere are reported.

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“…When the desired configuration ͑slenderness and eccentricity͒ is reached, manipulation ceases and the experiment runs alone: because of evaporation the liquid bridge volume continuously decreases and the liquid bridge breaks when the stability limit is reached. Such a volume reduction process is recorded by the CCD cameras, so that from the recorded images just before the breaking, the liquid bridge contours are determined by using standard interface detection techniques already used in liquid bridge problems, 6,7 and from these contours the liquid bridge volume, V ͑the minimum volume stability limit͒, as well as the volume of liquid between the smaller disk and the liquid bridge neck, V d , are calculated. To calculate such volumes it is assumed that liquid bridge cross sections are ellipses, which agrees with published analytical approximations for the shape of liquid bridge interfaces 3,8 ͑additional details can be obtained upon request from the authors͒.…”

mentioning

confidence: 99%

Minimum volume of long liquid bridges between noncoaxial, nonequal diameter circular disks under lateral acceleration

Meseguer¹,

Espino²,

Cuerva³

et al. 2005

Physics of Fluids

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The stability limit of minimum volume and the breaking dynamics of liquid bridges between nonequal, noncoaxial, circular supporting disks subject to a lateral acceleration were experimentally analyzed by working with liquid bridges of very small dimensions. Experimental results are compared with asymptotic theoretical predictions, with the agreement between experimental results and asymptotic ones being satisfactory. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.2107747͔In the simplest configuration a liquid bridge consists of an isothermal drop of liquid held by surface tension forces between two parallel, solid disks as shown in Fig. 1. Disregarding electric and magnetic fields effects, the equilibrium interface shapes and hydrostatic stability limits of liquid bridges are determined by the slenderness, ⌳ = L / ͑2R 0 ͒, where L is the distance between the supporting disks and the characteristic length R 0 is the mean radius, R 0 = ͑R 1 + R 2 ͒ /2; the ratio of the radius of the smaller disk, R 1 , to the radius of the larger one, R 2 , that is K = R 1 / R 2 , or the equivalent parameter h = ͑1−K͒ / ͑1+K͒ = ͑R 2 − R 1 ͒ / ͑R 2 + R 1 ͒; the dimensionless eccentricity, e = E / R 0 , 2E being the distance between the disks axes; the dimensionless volume, defined as the ratio of the actual volume V to the volume of a cylinder of the same length L and diameter 2R 0 : V = V / ͑R 0 2 L͒; and the lateral Bond number, B = ⌬gR 0 2 / , where ⌬ is the difference between the density of the liquid and the density of the surrounding medium, g is the lateral acceleration acting on the liquid drop, and is the surface tension.The stability limit of the minimum volume of long axisymmetric liquid bridges held between unequal, noncoaxial parallel circular supporting disks subject to lateral acceleration can be theoretically analyzed by using an analytical approximation based on the standard bifurcation theory ͑Lyapunov-Schmidt technique 1 ͒. This problem was first analyzed a decade ago, both analytically and experimentally, 2 with the following asymptotic expression for the stability limit of minimum volume obtained:where the eccentricity e is assumed to be positive when the relative position of the disks is as indicated in Fig. 1 ͑the smaller disk axis over the larger disk one͒. According to expression ͑1͒ the combined effect of lateral acceleration and eccentricity becomes maximum when the angle ␤ vanishes; this case is the only one considered in this Brief Communication. The variation of the minimum volume with the eccentricity for a lateral Bond number B = 0.05 and different values of the parameter h ͑assuming ␤ =0͒ of liquid bridges with slenderness ⌳ = 2.7 is shown in Fig. 2. Expression ͑1͒ is only valid when the liquid bridge configuration is close enough to the reference one ͑defined by the Rayleigh stability limit, ⌳ = , V =1, B = h = e =0͒, and far from this configuration of reference, Eq. ͑1͒ gives only a rough approximation of the influence on the stability limit of the different parameters considered. However, ...

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Detection of liquid bridge contours and its applications

Cited by 7 publications

References 14 publications

Dynamic stretching of a planar liquid bridge

Dynamic stretching of a planar liquid bridge

Study of floating zone profiles in materials grown by the laser‐heated pedestal growth technique under isostatic atmosphere

Minimum volume of long liquid bridges between noncoaxial, nonequal diameter circular disks under lateral acceleration

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