Critical Point in Space: A Quest for Universality

Beysens, Daniel

doi:10.1007/s12217-014-9373-1

Cited by 10 publications

(4 citation statements)

References 57 publications

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“…Periodic stripe patterns perpendicular to the axis of vibration were found by Beysens et al (2009) and Beysens (2014) in supercritical C0 2 on a sounding rocket provided by the European Space Agency. These were the first experiments on such patterns in weightlessness, and many of the investigations were continued on the ground in near-critical fluid using magnetic compensation of gravity, with the most recent among them aiming to study either the Faraday wave (Gandikota et al 2014a) or frozen wave (Gandikota et al 2014&) instability.…”

Section: P Salgado Sanchez and Othersmentioning

confidence: 91%

Interfacial phenomena in immiscible liquids subjected to vibrations in microgravity

et al. 2019

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We consider the response to periodic forcing between 5 Hz and 50 Hz of an interface separating immiscible fluids under the microgravity conditions of a parabolic flight. Two pairs of liquids with viscosity ratios differing by one order of magnitude are investigated. By combining experimental data with numerical simulations, we describe a variety of dynamics including harmonic and subharmonic (Faraday) waves, frozen waves and drop ejection, determining their thresholds and scaling properties when possible. Interaction between these various modes is facilitated in microgravity by the relative ease with which the interface can move, altering its orientation with respect to the forcing axis. The effects of key factors controlling pattern selection are analysed, including vibrational forcing, viscosity ratio, finite-size effects and residual gravity. Complex behaviour often arises with features on several spatial scales, such as Faraday waves excited on the interface of a larger columnar structure that develops due to the frozen wave instability – this type of state was previously seen in miscible fluid experiments but is described for the first time here in the immiscible case.

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Section: P Salgado Sanchez and Othersmentioning

confidence: 91%

Interfacial phenomena in immiscible liquids subjected to vibrations in microgravity

et al. 2019

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“…Many other space-based experiments have pointed out the importance of diffusive processes especially in microgravity conditions (De Lucas et al, 1989;Snell and Helliwell, 2005;Barmatz et al, 2007;Beysens, 2014;Hegseth et al, 2014;Shevtsova, 2012;Shevtsova et al, 2011;Shevtsova et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Shadowgraph Analysis of Non-equilibrium Fluctuations for Measuring Transport Properties in Microgravity in the GRADFLEX Experiment

Croccolo

Giraudet

Bataller

et al. 2016

Microgravity Sci. Technol.

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In a fluid system driven out of equilibrium by the presence of a gradient, fluctuations become long-ranged and their intensity diverges at large spatial scales. This divergence is prevented vertical confinement and, in a stable configuration, by gravity. Gravity and confinement also affect the dynamics of non-equilibrium fluctuations (NEFs). In fact, small wavelength fluctuations decay diffusively, while the decay of long wavelength ones is either dominated by buoyancy or by confinement. In normal gravity, from the analysis of the dynamics one can extract the diffusion coefficients as well as other transport properties. For example, in a thermodiffusion experiment one can measure the Soret coefficient. Under microgravity, the relaxation of fluctuations occurs by diffusion only and this prevents the determination of the Soret coefficient of a binary mixture from the study of the dynamics. In this work we propose an innovative self-referencing optical method for the determination of the thermal diffusion 2 ratio of a binary mixture that does not require previous knowledge of the temperature difference applied to the sample. The method relies on the determination of the ratio between the mean squared amplitude of concentration and temperature fluctuations. We investigate data from the GRADFLEX experiment, an experiment flown onboard the Russian satellite FOTON M3 in 2007. The investigated sample is a suspension of polystyrene polymer chains (MW=9,100g/mol, concentration 1.8wt%) in toluene, stressed by different temperature gradients. The use of a quantitative shadowgraph technique allows to perform measurements in the absence of delicate alignment and calibration procedures. The statics of the concentration and temperature NEFs are obtained and their ratio is computed. At large wave vectors the ratio becomes constant and is shown to be proportional to the thermal diffusion ratio of the sample.

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“…However, since the advent of space platforms, several experiments controlled by diffusion have been performed in a microgravity environment, which guarantees the absence of spurious convective motions. Notable examples include experiments on the crystallization of proteins 14 15 , critical phenomena 16 17 , the investigation of the influence of vibration on diffusion 18 19 , and of transport properties in ternary mixtures 20 . Therefore, the understanding of the onset of concentration fluctuations during diffusion in the absence of gravity represents an important feat both from the fundamental point of view, due to the lack of suitable theoretical models, and from the experimental point of view, due to the huge investment required to perform experiments in Space.…”

mentioning

confidence: 99%

Dynamic scaling for the growth of non-equilibrium fluctuations during thermophoretic diffusion in microgravity

Cerbino

Sun

Donev

et al. 2015

Sci Rep

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Diffusion processes are widespread in biological and chemical systems, where they play a fundamental role in the exchange of substances at the cellular level and in determining the rate of chemical reactions. Recently, the classical picture that portrays diffusion as random uncorrelated motion of molecules has been revised, when it was shown that giant non-equilibrium fluctuations develop during diffusion processes. Under microgravity conditions and at steady-state, non-equilibrium fluctuations exhibit scale invariance and their size is only limited by the boundaries of the system. In this work, we investigate the onset of non-equilibrium concentration fluctuations induced by thermophoretic diffusion in microgravity, a regime not accessible to analytical calculations but of great relevance for the understanding of several natural and technological processes. A combination of state of the art simulations and experiments allows us to attain a fully quantitative description of the development of fluctuations during transient diffusion in microgravity. Both experiments and simulations show that during the onset the fluctuations exhibit scale invariance at large wave vectors. In a broader range of wave vectors simulations predict a spinodal-like growth of fluctuations, where the amplitude and length-scale of the dominant mode are determined by the thickness of the diffuse layer.

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Critical Point in Space: A Quest for Universality

Cited by 10 publications

References 57 publications

Interfacial phenomena in immiscible liquids subjected to vibrations in microgravity

Interfacial phenomena in immiscible liquids subjected to vibrations in microgravity

Shadowgraph Analysis of Non-equilibrium Fluctuations for Measuring Transport Properties in Microgravity in the GRADFLEX Experiment

Dynamic scaling for the growth of non-equilibrium fluctuations during thermophoretic diffusion in microgravity

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