Service de Physique de l'Etat Condensé

2015 SPHYNX Publications

2015

 

Publications

 

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  • "Antiferromagnetic long-range spin ordering in Fe- and NiFe2-doped BaTiO3 multiferroic layers"
  • A. Barbier, T. Aghavnian, V. Badjeck, C. Mocuta, D. Stanescu, H. Magnan, C. L. Rountree, R. Belkhou, P. Ohresser and N. Jedrecy
    Physical Review B. 91:035417 (January, 2015)
    American Physical Society.
BibTeX:
@article{Barbier2015,
  author = {Barbier, A. and Aghavnian, T. and Badjeck, V. and Mocuta, C. and Stanescu, D. and Magnan, H. and Rountree, C. L. and Belkhou, R. and Ohresser, P. and Jedrecy, N.},
  title = {Antiferromagnetic long-range spin ordering in Fe- and NiFe2-doped BaTiO3 multiferroic layers},
  journal = {Physical Review B},
  publisher = {American Physical Society},
  year = {2015},
  volume = {91},
  pages = {035417},
  url = {http://link.aps.org/doi/10.1103/PhysRevB.91.035417},
  doi = {10.1103/PhysRevB.91.035417}
}
Abstract: This study investigates the mechanical response of sodium borosilicate (SBN) glasses as a function of their chemical composition. Vickers's indentation tests provide an estimate of the material hardness (HV) and indentation fracture toughness (K_C^VIF) plus the amount of densification/shear flow processes. Sodium content significantly impacts the glass behavior under a sharp indenter. Low sodium glasses maintain high connected networks and low Poisson's ratios ($). This entails significant densification processes during deformation. Conversely, glasses with high sodium content, i.e. large $, partake in a more depolymerized network favoring deformation by shear flow. As a consequence, indentation patterns differ depending on the processes occurring. Densification processes appear to hinder the formation of half-penny median–radial cracks. Increasing ? favors shear flow and residual stresses enhance the development of half-penny median–radial cracks. Hence, K_C^VIF decreases linearly with $.
BibTeX:
@article{Barlet2015,
  author = {Marina Barlet and Jean-Marc Delaye and Thibault Charpentier and Mickael Gennisson and Daniel Bonamy and Tanguy Rouxel and Cindy L. Rountree},
  title = {Hardness and toughness of sodium borosilicate glasses via Vickers's indentations },
  journal = {Journal of Non-Crystalline Solids },
  year = {2015},
  volume = {417-418},
  pages = {66 - 79},
  url = {http://www.sciencedirect.com/science/article/pii/S0022309315000538},
  doi = {10.1016/j.jnoncrysol.2015.02.005}
}
  • "Local Velocity Measurements in the Shrek Experiment at High Reynolds Number"
  • C. Baudet, M. B. Mardion, P. Bonnay, A. Braslau, B. Castaing, F. Chillà, L. Chevillard, F. Daviaud, P. Diribarne, B. Dubrulle, D. Durì, D. Faranda, B. Gallet, M. Gibert, A. Girard, B. Hébral, I. Moukharski, J. Poncet, J.-P. Moro, P.-E. Roche, B. Rousset, E. Rusaouën, B. Saint-Michel, J. Salort, E.-W. Saw, K. Steiros and C. Wiertel-Gasquet
    European Journal of Mechanics., In European Journal of Mechanics. (2015)
BibTeX:
@article{Baudet2015,
  author = {C. Baudet and M. Bon Mardion and P. Bonnay and A. Braslau and B. Castaing and F. Chillà and L. Chevillard and F. Daviaud and P. Diribarne and B. Dubrulle and D. Durì and D. Faranda and B. Gallet and M. Gibert and A. Girard and B. Hébral and I. Moukharski and J.M. Poncet and J.-P. Moro and P.-E. Roche and B. Rousset and E. Rusaouën and B. Saint-Michel and J. Salort and E-W. Saw and K. Steiros and C. Wiertel-Gasquet},
  title = {Local Velocity Measurements in the Shrek Experiment at High Reynolds Number},
  booktitle = {European Journal of Mechanics},
  journal = {European Journal of Mechanics},
  year = {2015}
}
Abstract: Zero-point quantum fluctuations of the electromagnetic vacuum create the widely known London-van der Waals attractive force between two atoms. Recently, there has been a revived interest in the interaction of rotating matter with the quantum vacuum. Here, we consider a rotating pair of atoms maintained by London-van der Waals forces and calculate the frictional torque they experience due to zero-point radiation. Using a semiclassical framework derived from the fluctuation dissipation theorem, we take into account the full electrostatic coupling between induced dipoles. Considering the case of zero temperature only, we find a braking torque proportional to the angular velocity and to the third power of the fine structure constant. Although very small compared to London-van derWaals attraction, the torque is strong enough to induce the formation of dimers in binary collisions. This new friction phenomenon at the atomic level should induce a paradigm change in the explanation of irreversibility.
BibTeX:
@article{Bercegol2015,
  author = {Bercegol, Herve and Lehoucq, Roland},
  title = {Vacuum Friction on a Rotating Pair of Atoms},
  journal = {Physical Review Letters},
  year = {2015},
  volume = {115},
  number = {9},
  pages = {090402},
  doi = {10.1103/PhysRevLett.115.090402}
}
  • "Comparison between Smoluchowski and Boltzmann approaches for self-propelled rods"
  • E. Bertin, A. Baskaran, H. Chate and M. C. Marchetti
    Physical Review E. 92(4):042141 (October, 2015)
Abstract: Considering systems of self-propelled polar particles with nematic interactions ("rods"), we compare the continuum equations describing the evolution of polar and nematic order parameters, derived either from Smoluchowski or Boltzmann equations. Our main goal is to understand the discrepancies between the continuum equations obtained so far in both frameworks. We first show that, in the simple case of point-like particles with only alignment interactions, the continuum equations obtained have the same structure in both cases. We further study, in the Smoluchowski framework, the case where an interaction force is added on top of the aligning torque. This clarifies the origin of the additional terms obtained in previous works. Our observations lead us to emphasize the need for a more involved closure scheme than the standard normal form of the distribution when dealing with active systems.
BibTeX:
@article{Bertin2015,
  author = {Bertin, Eric and Baskaran, Aparna and Chate, Hugues and Marchetti, M. Cristina},
  title = {Comparison between Smoluchowski and Boltzmann approaches for self-propelled rods},
  journal = {Physical Review E},
  year = {2015},
  volume = {92},
  number = {4},
  pages = {042141},
  doi = {10.1103/PhysRevE.92.042141}
}
  • "Thermoelectric energy recovery at ionic-liquid/electrode interface"
  • M. Bonetti, S. Nakamae, B. T. Huang, T. J. Salez, C. Wiertel-Gasquet and M. Roger
    Journal of Chemical Physics. 142(24):244708 (June, 2015)
Abstract: A thermally chargeable capacitor containing a binary solution of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide in acetonitrile is electrically charged by applying a temperature gradient to two ideally polarisable electrodes. The corresponding thermoelectric coefficient is -1.7 mV/K for platinum foil electrodes and -0.3 mV/K for nanoporous carbon electrodes. Stored electrical energy is extracted by discharging the capacitor through a resistor. The measured capacitance of the electrode/ionic-liquid interface is 5 mu F for each platinum electrode while it becomes four orders of magnitude larger, approximate to 36 mF, for a single nanoporous carbon electrode. Reproducibility of the effect through repeated charging-discharging cycles under a steady-state temperature gradient demonstrates the robustness of the electrical charging process at the liquid/electrode interface. The acceleration of the charging by convective flows is also observed. This offers the possibility to convert waste-heat into electric energy without exchanging electrons between ions and electrodes, in contrast to what occurs in most thermogalvanic cells. (C) 2015 AIP Publishing LLC.
BibTeX:
@article{Bonetti2015a,
  author = {Bonetti, Marco and Nakamae, Sawako and Huang, Bo Tao and Salez, Thomas J. and Wiertel-Gasquet, Cecile and Roger, Michel},
  title = {Thermoelectric energy recovery at ionic-liquid/electrode interface},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {142},
  number = {24},
  pages = {244708},
  doi = {10.1063/1.4923199}
}
  • "Collective response to perturbations in a data-driven fish school model"
  • D. S. Calovi, U. Lopez, P. Schuhmacher, H. Chate, C. Sire and G. Theraulaz
    Journal of the Royal Society Interface. 12(104):20141362 (March, 2015)
Abstract: Fish schools are able to display a rich variety of collective states and behavioural responses when they are confronted by threats. However, a school's response to perturbations may be different depending on the nature of its collective state. Here we use a previously developed data-driven fish school model to investigate how the school responds to perturbations depending on its different collective states, we measure its susceptibility to such perturbations, and exploit its relation with the intrinsic fluctuations in the school. In particular, we study how a single or a small number of perturbing individuals whose attraction and alignment parameters are different from those of the main population affect the long-term behaviour of a school. We find that the responsiveness of the school to the perturbations is maximum near the transition region between milling and schooling states where the school exhibits multistability and regularly shifts between these two states. It is also in this region that the susceptibility, and hence the fluctuations, of the polarization order parameter is maximal. We also find that a significant school's response to a perturbation only happens below a certain threshold of the noise to social interactions ratio.
BibTeX:
@article{Calovi2015,
  author = {Calovi, Daniel S. and Lopez, Ugo and Schuhmacher, Paul and Chate, Hugues and Sire, Clement and Theraulaz, Guy},
  title = {Collective response to perturbations in a data-driven fish school model},
  journal = {Journal of the Royal Society Interface},
  year = {2015},
  volume = {12},
  number = {104},
  pages = {20141362},
  doi = {10.1098/rsif.2014.1362}
}
  • "Effect of the porosity on the fracture surface roughness of sintered materials: From anisotropic to isotropic self-affine scaling"
  • T. Cambonie, J. Bares, M. L. Hattali, D. Bonamy, V. Lazarus and H. Auradou
    Physical Review E. 91:012406 (Jan, 2015)
    American Physical Society.
BibTeX:
@article{Cambonie2015,
  author = {Cambonie, T. and Bares, J. and Hattali, M. L. and Bonamy, D. and Lazarus, V. and Auradou, H.},
  title = {Effect of the porosity on the fracture surface roughness of sintered materials: From anisotropic to isotropic self-affine scaling},
  journal = {Physical Review E},
  publisher = {American Physical Society},
  year = {2015},
  volume = {91},
  pages = {012406},
  url = {http://link.aps.org/doi/10.1103/PhysRevE.91.012406},
  doi = {10.1103/PhysRevE.91.012406}
}
  • "Disentangling inertial waves from eddy turbulence in a forced rotating- turbulence experiment"
  • A. Campagne, B. Gallet, F. Moisy and P.-P. Cortet
    Physical Review E. 91(4):043016 (April, 2015)
Abstract: We present a spatiotemporal analysis of a statistically stationary rotating-turbulence experiment, aiming to extract a signature of inertial waves and to determine the scales and frequencies at which they can be detected. The analysis uses two-point spatial correlations of the temporal Fourier transform of velocity fields obtained from time-resolved stereoscopic particle image velocimetry measurements in the rotating frame. We quantify the degree of anisotropy of turbulence as a function of frequency and spatial scale. We show that this space-time-dependent anisotropy is well described by the dispersion relation of linear inertial waves at large scale, while smaller scales are dominated by the sweeping of the waves by fluid motion at larger scales. This sweeping effect is mostly due to the low-frequency quasi-two-dimensional component of the turbulent flow, a prominent feature of our experiment that is not accounted for by wave-turbulence theory. These results question the relevance of this theory for rotating turbulence at the moderate Rossby numbers accessible in laboratory experiments, which are relevant to most geophysical and astrophysical flows.
BibTeX:
@article{Campagne2015,
  author = {Campagne, Antoine and Gallet, Basile and Moisy, Frederic and Cortet, Pierre-Philippe},
  title = {Disentangling inertial waves from eddy turbulence in a forced rotating- turbulence experiment},
  journal = {Physical Review E},
  year = {2015},
  volume = {91},
  number = {4},
  pages = {043016},
  doi = {10.1103/PhysRevE.91.043016}
}
  • "Criticality in the slowed-down boiling crisis at zero gravity"
  • T. Charignon, P. Lloveras, D. Chatain, L. Truskinovsky, E. Vives, D. Beysens and V. S. Nikolayev
    Physical Review E. 91:053007 (May, 2015)
    American Physical Society.
BibTeX:
@article{Charignon2015,
  author = {Charignon, T. and Lloveras, P. and Chatain, D. and Truskinovsky, L. and Vives, E. and Beysens, D. and Nikolayev, V. S.},
  title = {Criticality in the slowed-down boiling crisis at zero gravity},
  journal = {Physical Review E},
  publisher = {American Physical Society},
  year = {2015},
  volume = {91},
  pages = {053007},
  url = {http://link.aps.org/doi/10.1103/PhysRevE.91.053007},
  doi = {10.1103/PhysRevE.91.053007}
}
  • "The switching between zonal and blocked mid-latitude atmospheric circulation: a dynamical system perspective"
  • D. Faranda, G. Masato, N. Moloney, Y. Sato, F. Daviaud, B. Dubrulle and P. Yiou
    Climate Dynamics. :1-13 (2015)
Abstract: Atmospheric mid-latitude circulation is dominated by a zonal, westerly flow. Such a flow is generally symmetric, but it can be occasionally broken up by blocking anticyclones. The subsequent asymmetric flow can persist for several days. In this paper, we apply new mathematical tools based on the computation of an extremal index in order to reexamine the dynamical mechanisms responsible for the transitions between zonal and blocked flows. We discard the claim that mid-latitude circulation features two distinct stable equilibria or chaotic regimes, in favor of a simpler mechanism that is well understood in dynamical systems theory: we identify the blocked flow as an unstable fixed point (or saddle point) of a single basin chaotic attractor, dominated by the westerlies regime. We also analyze the North Atlantic Oscillation and the Arctic Oscillation atmospheric indices, whose behavior is often associated with the transition between the two circulation regimes, and investigate analogies and differences with the bidimensional blocking indices. We find that the Arctic Oscillation index, which can be thought as a proxy for a hemispheric average of the Tibaldi--Molteni blocking index, tracks unstable fixed points. On the other hand, the North Atlantic Oscillation, representative only for local properties of the North Atlantic blocking dynamics, does not show any trace of the presence of unstable fixed points of the dynamics.
BibTeX:
@article{Faranda2015,
  author = {D. Faranda and G. Masato and N. Moloney and Y. Sato and F. Daviaud and B. Dubrulle and P. Yiou},
  title = {The switching between zonal and blocked mid-latitude atmospheric circulation: a dynamical system perspective},
  journal = {Climate Dynamics},
  year = {2015},
  pages = {1--13},
  url = {http://dx.doi.org/10.1007/s00382-015-2921-6},
  doi = {10.1007/s00382-015-2921-6}
}
  • "Early warnings indicators of financial crises via auto regressive moving average models"
  • D. Faranda, F. M. E. Pons, E. Giachino, S. Vaienti and B. Dubrulle
    Communications in Nonlinear Science and Numerical Simulation. 29(1–3):233-239 (December, 2015)
Abstract: Abstract We address the problem of defining early warning indicators of financial crises. To this purpose, we fit the relevant time series through a class of linear models, known as auto-regressive moving-average (ARMA(p, q)) models. By running such a fit on intervals of the time series that can be considered stationary, we first determine the typical ARMA( p ¯ , q ¯ ). Such a model exists over windows of about 60 days and turns out to be an AR(1). For each of them, we estimate the relative parameters, i.e. ϕi and θi on the same running windows. Then, we define a distance ϒ from such typical model in the space of the likelihood functions and compute it on short intervals of stocks indexes. Such a distance is expected to increase when the stock market deviates from its normal state for the modifications of the volatility which happen commonly before a crisis. We observe that ϒ computed for the Dow Jones, Standard and Poor’s and EURO STOXX 50 indexes provides an effective early warning indicator which allows for detection of the crisis events that showed precursors.
BibTeX:
@article{Faranda2015a,
  author = {D. Faranda and F. M. E. Pons and E. Giachino and S. Vaienti and B. Dubrulle},
  title = {Early warnings indicators of financial crises via auto regressive moving average models},
  journal = {Communications in Nonlinear Science and Numerical Simulation},
  year = {2015},
  volume = {29},
  number = {1–3},
  pages = {233--239},
  url = {http://www.sciencedirect.com/science/article/pii/S1007570415001653}
}
Abstract: We consider the flow of a Newtonian fluid in a three-dimensional domain, rotating about a vertical axis and driven by a vertically invariant horizontal body force. This system admits vertically invariant solutions that satisfy the 2D Navier-Stokes equation. At high Reynolds number and without global rotation, such solutions are usually unstable to three-dimensional perturbations. By contrast, for strong enough global rotation, we prove rigorously that the 2D (and possibly turbulent) solutions are stable to vertically dependent perturbations. We first consider the 3D rotating Navier-Stokes equation linearized around a statistically steady 2D flow solution. We show that this base flow is linearly stable to vertically dependent perturbations when the global rotation is fast enough: under a Reynolds-number-dependent threshold value Ro(c)(Re) of the Rossby number, the flow becomes exactly 2D in the long-time limit, provided that the initial 3D perturbations are small. We call this property linear two-dimensionalization. We compute explicit lower bounds on Ro(c)(Re) and therefore determine regions of the parameter space. (Re, Ro) where such exact two-dimensionalization takes place. We present similar results in terms of the forcing strength instead of the root-mean-square velocity: the global attractor of the 2D Navier-Stokes equation is linearly stable to vertically dependent perturbations when the forcing-based Rossby number Ro((f)) is lower than a Grashof-number-dependent threshold value Ro(c)((f))(Gr). We then consider the fully nonlinear 3D rotating Navier-Stokes equation and prove absolute two-dimensionalization: we show that, below some threshold value Ro(abs)((f))(Gr) of the forcing-based Rossby number, the flow becomes two-dimensional in the long-time limit, regardless of the initial condition (including initial 3D perturbations of arbitrarily large amplitude). These results shed some light on several fundamental questions of rotating turbulence: for arbitrary Reynolds number Re and small enough Rossby number, the system is attracted towards purely 2D flow solutions, which display no energy dissipation anomaly and no cyclone-anticyclone asymmetry. Finally, these results challenge the applicability of wave turbulence theory to describe stationary rotating turbulence in bounded domains.
BibTeX:
@article{Gallet2015a,
  author = {Gallet, Basile},
  title = {Exact two-dimensionalization of rapidly rotating large-Reynolds-number flows},
  journal = {Journal of Fluid Mechanics},
  year = {2015},
  volume = {783},
  pages = {412--447},
  doi = {10.1017/jfm.2015.569}
}
  • "Exact two-dimensionalization of low-magnetic-Reynolds-number flows subject to a strong magnetic field"
  • B. Gallet and C. R. Doering
    Journal of Fluid Mechanics. 773:154-177 (June, 2015)
Abstract: We investigate the behaviour of flows, including turbulent flows, driven by a horizontal body force and subject to a vertical magnetic field, with the following question in mind: for a very strong applied magnetic field, is the flow mostly two-dimensional, with remaining weak three-dimensional fluctuations, or does it become exactly 2-D, with no dependence along the vertical direction? We first focus on the quasi-static approximation, i. e. the asymptotic limit of vanishing magnetic Reynolds number, Rm << 1: we prove that the flow becomes exactly 2-D asymptotically in time, regardless of the initial condition and provided that the interaction parameter N is larger than a threshold value. We call this property absolute two-dimensionalization: the attractor of the system is necessarily a (possibly turbulent) 2-D flow. We then consider the full magnetohydrodynamic (MHD) equations and prove that, for low enough Rm and large enough N, the flow becomes exactly 2-D in the long-time limit provided the initial vertically dependent perturbations are infinitesimal. We call this phenomenon linear two-dimensionalization: the (possibly turbulent) 2-D flow is an attractor of the dynamics, but it is not necessarily the only attractor of the system. Some 3-D attractors may also exist and be attained for strong enough initial 3-D perturbations. These results shed some light on the existence of a dissipation anomaly for MHD flows subject to a strong external magnetic field.
BibTeX:
@article{Gallet2015,
  author = {Gallet, Basile and Doering, Charles R.},
  title = {Exact two-dimensionalization of low-magnetic-Reynolds-number flows subject to a strong magnetic field},
  journal = {Journal of Fluid Mechanics},
  year = {2015},
  volume = {773},
  pages = {154--177},
  doi = {10.1017/jfm.2015.232}
}
  • "Wave-turbulence description of interacting particles: Klein-Gordon model with a Mexican-hat potential"
  • B. Gallet, S. Nazarenko and B. Dubrulle
    Physical Review E. 92(1):012909 (July, 2015)
Abstract: In field theory, particles are waves or excitations that propagate on the fundamental state. In experiments or cosmological models, one typically wants to compute the out-of-equilibrium evolution of a given initial distribution of such waves. Wave turbulence deals with out-of-equilibrium ensembles of weakly nonlinear waves, and is therefore well suited to address this problem. As an example, we consider the complex Klein-Gordon equation with a Mexican-hat potential. This simple equation displays two kinds of excitations around the fundamental state: massive particles and massless Goldstone bosons. The former are waves with a nonzero frequency for vanishing wave number, whereas the latter obey an acoustic dispersion relation. Using wave-turbulence theory, we derive wave kinetic equations that govern the coupled evolution of the spectra of massive and massless waves. We first consider the thermodynamic solutions to these equations and study the wave condensation transition, which is the classical equivalent of Bose-Einstein condensation. We then focus on nonlocal interactions in wave-number space: we study the decay of an ensemble of massive particles into massless ones. Under rather general conditions, these massless particles accumulate at low wave number. We study the dynamics of waves coexisting with such a strong condensate, and we compute rigorously a nonlocal Kolmogorov-Zakharov solution, where particles are transferred nonlocally to the condensate, while energy cascades towards large wave numbers through local interactions. This nonlocal cascading state constitutes the intermediate asymptotics between the initial distribution of waves and the thermodynamic state reached in the long-time limit.
BibTeX:
@article{Gallet2015b,
  author = {Gallet, Basile and Nazarenko, Sergey and Dubrulle, Berengere},
  title = {Wave-turbulence description of interacting particles: Klein-Gordon model with a Mexican-hat potential},
  journal = {Physical Review E},
  year = {2015},
  volume = {92},
  number = {1},
  pages = {012909},
  doi = {10.1103/PhysRevE.92.012909}
}
  • "The stability of stratified spatially periodic shear flows at low Peclet number"
  • P. Garaud, B. Gallet and T. Bischoff
    Physics of Fluids. 27(8):084104 (August, 2015)
Abstract: This work addresses the question of the stability of stratified, spatially periodic shear flows at low Peclet number but high Reynolds number. This little-studied limit is motivated by astrophysical systems, where the Prandtl number is often very small. Furthermore, it can be studied using a reduced set of "low-Peclet-number equations" proposed by Lignisres ["The small-Peclet-number approximation in stellar radiative zones," Astron. Astrophys. 348, 933-939 (1999)]. Through a linear stability analysis, we first determine the conditions for instability to infinitesimal perturbations. We formally extend Squire's theorem to the low-Peclet-number equations, which shows that the first unstable mode is always two-dimensional. We then perform an energy stability analysis of the low-Peclet-number equations and prove that for a given value of the Reynolds number, above a critical strength of the stratification, any smooth periodic shear flow is stable to perturbations of arbitrary amplitude. In that parameter regime, the flow can only be laminar and turbulent mixing does not take place. Finding that the conditions for linear and energy stability are different, we thus identify a region in parameter space where finite-amplitude instabilities could exist. Using direct numerical simulations, we indeed find that the system is subject to such finite-amplitude instabilities. We determine numerically how far into the linearly stable region of parameter space turbulence can be sustained. (C) 2015 AIP Publishing LLC.
BibTeX:
@article{Garaud2015,
  author = {Garaud, Pascale and Gallet, Basile and Bischoff, Tobias},
  title = {The stability of stratified spatially periodic shear flows at low Peclet number},
  journal = {Physics of Fluids},
  year = {2015},
  volume = {27},
  number = {8},
  pages = {084104},
  doi = {10.1063/1.4928164}
}
  • "Statistics of injected power on a bouncing ball subjected to a randomly vibrating piston"
  • A. Garcia-Cid, P. Gutierrez, C. Falcon, S. Aumaitre and E. Falcon
    Physical Review E. 92(3):032915 (September, 2015)
Abstract: We present an experimental study on the statistical properties of the injected power needed to maintain an inelastic ball bouncing constantly on a randomly accelerating piston in the presence of gravity. We compute the injected power at each collision of the ball with the moving piston by measuring the velocity of the piston and the force exerted on the piston by the ball. The probability density function of the injected power has its most probable value close to zero and displays two asymmetric exponential tails, depending on the restitution coefficient, the piston acceleration, and its frequency content. This distribution can be deduced from a simple model assuming quasi-Gaussian statistics for the force and velocity of the piston.
BibTeX:
@article{Garcia-Cid2015,
  author = {Garcia-Cid, Alfredo and Gutierrez, Pablo and Falcon, Claudio and Aumaitre, Sebastien and Falcon, Eric},
  title = {Statistics of injected power on a bouncing ball subjected to a randomly vibrating piston},
  journal = {Physical Review E},
  year = {2015},
  volume = {92},
  number = {3},
  pages = {032915},
  doi = {10.1103/PhysRevE.92.032915}
}
  • "Intermittent collective dynamics emerge from conflicting imperatives in sheep herds"
  • F. Ginelli, F. Peruani, M.-H. Pillot, H. Chate, G. Theraulaz and R. Bon
    Proceedings of the National Academy of Sciences of the United States of America. 112(41):12729-12734 (October, 2015)
Abstract: Among the many fascinating examples of collective behavior exhibited by animal groups, some species are known to alternate slow group dispersion in space with rapid aggregation phenomena induced by a sudden behavioral shift at the individual level. We study this phenomenon quantitatively in large groups of grazing Merino sheep under controlled experimental conditions. Our analysis reveals strongly intermittent collective dynamics consisting of fast, avalanche-like regrouping events distributed on all experimentally accessible scales. As a proof of principle, we introduce an agent-based model with individual behavioral shifts, which we show to account faithfully for all collective properties observed. This offers, in turn, an insight on the individual stimulus/response functions that can generate such intermittent behavior. In particular, the intensity of sheep allelomimetic behavior plays a key role in the group's ability to increase the per capita grazing surface while minimizing the time needed to regroup into a tightly packed configuration. We conclude that the emergent behavior reported probably arises from the necessity to balance two conflicting imperatives: ( i) the exploration of foraging space by individuals and ( ii) the protection from predators offered by being part of large, cohesive groups. We discuss our results in the context of the current debate about criticality in biology.
BibTeX:
@article{Ginelli2015,
  author = {Ginelli, Francesco and Peruani, Fernando and Pillot, Marie-Helene and Chate, Hugues and Theraulaz, Guy and Bon, Richard},
  title = {Intermittent collective dynamics emerge from conflicting imperatives in sheep herds},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2015},
  volume = {112},
  number = {41},
  pages = {12729--12734},
  doi = {10.1073/pnas.1503749112}
}
  • "Experimental study on the clustering of floaters on the free surface of a turbulent flow"
  • P. Gutierrez and S. Aumaître
    Physical Review E. Submitted (2015)
BibTeX:
@article{Gutierrez2015,
  author = {P. Gutierrez and S. Aumaître},
  title = {Experimental study on the clustering of floaters on the free surface of a turbulent flow},
  journal = {Physical Review E},
  year = {2015},
  volume = {Submitted},
  note = {http://arxiv.org/abs/1410.7824}
}
  • "Finite-size scaling, dynamic fluctuations, and hyperscaling relation in the Kuramoto model"
  • H. Hong, H. Chate, L.-H. Tang and H. Park
    Physical Review E (Statistical, Nonlinear, and Soft Matter Physics). 92(2):022122 (8 pp.)-022122 (2015)
Abstract: We revisit the Kuramoto model to explore the finite-size scaling (FSS) of the order parameter and its dynamic fluctuations near the onset of the synchronization transition, paying particular attention to effects induced by the randomness of the intrinsic frequencies of oscillators. For a population of size N, we study two ways of sampling the intrinsic frequencies according to the same given unimodal distribution g(omega). In the ldquo randomrdquo case, frequencies are generated independently in accordance with g(omega), which gives rise to oscillator number fluctuation within any given frequency interval. In the ldquo regularrdquo case, the N frequencies are generated in a deterministic manner that minimizes the oscillator number fluctuations, leading to quasiuniformly spaced frequencies in the population. We find that the two samplings yield substantially different finite-size properties with clearly distinct scaling exponents. Moreover, the hyperscaling relation between the order parameter and its fluctuations is valid in the regular case, but it is violated in the random case. In this last case, a self-consistent mean-field theory that completely ignores dynamic fluctuations correctly predicts the FSS exponent of the order parameter but not its critical amplitude.
BibTeX:
@article{Hong2015,
  author = {Hyunsuk Hong and Chate, H. and Lei-Han Tang and Hyunggyu Park},
  title = {Finite-size scaling, dynamic fluctuations, and hyperscaling relation in the Kuramoto model},
  journal = {Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)},
  year = {2015},
  volume = {92},
  number = {2},
  pages = {022122 (8 pp.)--022122},
  doi = {10.1103/PhysRevE.92.022122}
}
  • "Thermoelectricity and thermodiffusion in charged colloids"
  • B. T. Huang, M. Roger, M. Bonetti, T. J. Salez, C. Wiertel-Gasquet, E. Dubois, R. Cabreira Gomes, G. Demouchy, G. Meriguet, V. Peyre, M. Kouyate, C. L. Filomeno, J. Depeyrot, F. A. Tourinho, R. Perzynski and S. Nakamae
    Journal of Chemical Physics. 143(5):054902 (5 pp.)-054902 (July, 2015)
Abstract: The Seebeck and Soret coefficients of ionically stabilized suspension of maghemite nanoparticles in dimethyl sulfoxide are experimentally studied as a function of nanoparticle volume fraction. In the presence of a temperature gradient, the charged colloidal nanoparticles experience both thermal drift due to their interactions with the solvent and electric forces proportional to the internal thermoelectric field. The resulting thermodiffusion of nanoparticles is observed through forced Rayleigh scattering measurements, while the thermoelectric field is accessed through voltage measurements in a thermocell. Both techniques provide independent estimates of nanoparticle's entropy of transfer as high as 82 meV K -1. Such a property may be used to improve the thermoelectric coefficients in liquid thermocells.
BibTeX:
@article{Huang2015a,
  author = {Huang, B. T. and Roger, M. and Bonetti, M. and Salez, T. J. and Wiertel-Gasquet, C. and Dubois, E. and Cabreira Gomes, R. and Demouchy, G. and Meriguet, G. and Peyre, V. and Kouyate, M. and Filomeno, C. L. and Depeyrot, J. and Tourinho, F. A. and Perzynski, R. and Nakamae, S.},
  title = {Thermoelectricity and thermodiffusion in charged colloids},
  journal = {Journal of Chemical Physics},
  year = {2015},
  volume = {143},
  number = {5},
  pages = {054902 (5 pp.)--054902},
  doi = {10.1063/1.4927665}
}
Abstract: Abstract We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation–condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid–liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact line singularity. The liquid mass is conserved: evaporation existing on a part of the meniscus and condensation occurring over another part compensate exactly each other. However, numerical estimations carried out for three common fluids (ethanol, water and glycerol) at the ambient conditions show that the characteristic length scales are tiny.
BibTeX:
@article{Janecek2015,
  author = {V. Janecek and F. Doumenc and B. Guerrier and V.S. Nikolayev},
  title = {Can hydrodynamic contact line paradox be solved by evaporation–condensation?},
  journal = {Journal of Colloid and Interface Science},
  year = {2015},
  volume = {460},
  pages = {329 - 338},
  url = {http://www.sciencedirect.com/science/article/pii/S0021979715301570},
  doi = {10.1016/j.jcis.2015.08.062}
}
  • "Global vs local energy dissipation: The energy cycle of the turbulent von Karman flow"
  • D. Kuzzay, D. Faranda and B. Dubrulle
    Physics of Fluids. 27(7):075105 (July, 2015)
Abstract: In this paper, we investigate the relations between global and local energy transfers in a turbulent von Karman flow. The goal is to understand how and where energy is dissipated in such a flow and to reconstruct the energy cycle in an experimental device where local as well as global quantities can be measured. In order to do so, we use particle image velocimetry (PIV) measurements and we model the Reynolds stress tensor to take subgrid scales into account. This procedure involves a free parameter that is calibrated using angular momentum balance. We then estimate the local and global mean injected and dissipated powers for several types of impellers, for various Reynolds numbers, and for various flow topologies. These PIV estimates are then compared with direct injected power estimates provided by torque measurements at the impellers. The agreement between PIV estimates and direct measurements depends on the flow topology. In symmetric situations, we are able to capture up to 90% of the actual global energy dissipation rate. However, our results become increasingly inaccurate as the shear layer responsible for most of the dissipation approaches one of the impellers and cannot be resolved by our PIV setup. Finally, we show that a very good agreement between PIV estimates and direct measurements is obtained using a new method based on the work of Duchon and Robert ["Inertial energy dissipation for weak solutions of incompressible Euler and Navier-Stokes equations," Nonlinearity 13, 249-225 (2000)] which generalizes the Karman-Howarth equation to nonisotropic, nonhomogeneous flows. This method provides parameter-free estimates of the energy dissipation rate as long as the smallest resolved scale lies in the inertial range. These results are used to evidence a well-defined stationary energy cycle within the flow in which most of the energy is injected at the top and bottom impellers and dissipated within the shear layer. The influence of the mean flow geometry and the Reynolds number on this energy cycle is studied for a wide range of parameters. (C) 2015 AIP Publishing LLC.
BibTeX:
@article{Kuzzay2015,
  author = {Kuzzay, Denis and Faranda, Davide and Dubrulle, Berengere},
  title = {Global vs local energy dissipation: The energy cycle of the turbulent von Karman flow},
  journal = {Physics of Fluids},
  year = {2015},
  volume = {27},
  number = {7},
  pages = {075105},
  doi = {10.1063/1.4923750}
}
Abstract: We show that memory, in the form of underdamped angular dynamics, is a crucial ingredient for the collective properties of self-propelled particles. Using Vicsek-style models with an Ornstein-Uhlenbeck process acting on angular velocity, we uncover a rich variety of collective phases not observed in usual overdamped systems, including vortex lattices and active foams. In a model with strictly nematic interactions the smectic arrangement of Vicsek waves giving rise to global polar order is observed. We also provide a calculation of the effective interaction between vortices in the case where a telegraphic noise process is at play, explaining thus the emergence and structure of the vortex lattices observed here and in motility assay experiments.
BibTeX:
@article{Nagai2015,
  author = {Nagai, Ken H. and Sumino, Yutaka and Montagne, Raul and Aranson, Igor S. and Chate, Hugues},
  title = {Collective Motion of Self-Propelled Particles with Memory},
  journal = {Physical Review Letters},
  year = {2015},
  volume = {114},
  number = {16},
  pages = {168001},
  doi = {10.1103/PhysRevLett.114.168001}
}
  • "Boiling Crisis Dynamics: Low Gravity Experiments at High Pressure"
  • V. Nikolayev, Y. Garrabos, C. Lecoutre, T. Charignon, D. Hitz, D. Chatain, R. Guillaument, S. Marre and D. Beysens
    Microgravity Science and Technology. :1-8 (2015)
    Springer Netherlands.
BibTeX:
@article{Nikolayev2015a,
  author = {Nikolayev, V. and Garrabos, Y. and Lecoutre, C. and Charignon, T. and Hitz, D. and Chatain, D. and Guillaument, R. and Marre, S. and Beysens, D.},
  title = {Boiling Crisis Dynamics: Low Gravity Experiments at High Pressure},
  journal = {Microgravity Science and Technology},
  publisher = {Springer Netherlands},
  year = {2015},
  pages = {1-8},
  url = {http://dx.doi.org/10.1007/s12217-015-9447-8},
  doi = {10.1007/s12217-015-9447-8}
}
Abstract: Abstract The direct conversion of solar light into chemical energy or fuel through photoelectrochemical water splitting is promising as a clean hydrogen production solution. Ti-doped hematite (Ti:α-Fe2O3) is a potential key photoanode material, which despite its optimal band gap, excellent chemical stability, abundance, non-toxicity and low cost, still has to be improved. Here we give evidence of a drastic improvement of the water splitting performances of Ti-doped hematite photoanodes upon a HCl wet-etching. In addition to the topography investigation by atomic force microscopy, a detailed determination of the local electronic structure has been carried out in order to understand the phenomenon and to provide new insights in the understanding of solar water splitting. Using synchrotron radiation based spectromicroscopy (X-PEEM), we investigated the X-ray absorption spectral features at the L3 Fe edge of the as grown surface and of the wet-etched surface on the very same sample thanks to patterning. We show that HCl wet etching leads to substantial surface modifications of the oxide layer including increased roughness and chemical reduction (presence of Fe2 +) without changing the band gap. We demonstrate that these changes are profitable and correlated to the drastic changes of the photocatalytic activity.
BibTeX:
@article{Rioult2015,
  author = {M. Rioult and R. Belkhou and H. Magnan and D. Stanescu and S. Stanescu and F. Maccherozzi and C. Rountree and A. Barbier},
  title = {Local electronic structure and photoelectrochemical activity of partial chemically etched Ti-doped hematite },
  journal = {Surface Science},
  year = {2015},
  volume = {In Press},
  pages = { },
  url = {http://www.sciencedirect.com/science/article/pii/S0039602815000059},
  doi = {10.1016/j.susc.2015.01.002}
}
  • "Cryogenic turbulence test facilities at CEA/SBT"
  • B. Rousset, C. Baudet, M. B. Mardion, M. Bourgoin, A. Braslau, F. Daviaud, P. Diribarne, B. Dubrulle, Y. Gagne, B. Gallet, M. Gibert, A. Girard, T. Lehner, I. Moukharski and F. Sy
    IOP Conference Series: Materials Science and Engineering. 101(1):012187 (2015)
Abstract: Recently, CEA Grenoble SBT has designed, built and tested three liquid helium facilities dedicated to turbulence studies. All these experiments can operate either in HeI or HeII within the same campaign. The three facilities utilize moving parts inside liquid helium. The SHREK experiment is a von Kármán swirling flow between 0.72 m diameter counterrotating disks equipped with blades. The HeJet facility is used to produce a liquid helium free jet inside a 0.200 m I.D., 0.47 m length stainless steel cylindrical testing chamber. The OGRES experiment consists of an optical cryostat equipped with a particle injection device and an oscillating grid. We detail specific techniques employed to accommodate these stringent specifications. Solutions for operating these facilities without bubbles nor boiling/cavitation are described. Control parameters as well as Reynolds number and temperature ranges are given.
BibTeX:
@article{Rousset2015,
  author = {B Rousset and C Baudet and M Bon Mardion and M Bourgoin and A Braslau and F Daviaud and P Diribarne and B Dubrulle and Y Gagne and B
Gallet and M Gibert and A Girard and T Lehner and I Moukharski and F Sy},
  title = {Cryogenic turbulence test facilities at CEA/SBT},
  journal = {IOP Conference Series: Materials Science and Engineering},
  year = {2015},
  volume = {101},
  number = {1},
  pages = {012187},
  url = {http://stacks.iop.org/1757-899X/101/i=1/a=012187}
}
  • "Pattern formation in flocking models: A hydrodynamic description"
  • A. P. Solon, J.-B. Caussin, D. Bartolo, H. Chate and J. Tailleur
    Physical Review E. 92(6):062111 (December, 2015)
Abstract: We study in detail the hydrodynamic theories describing the transition to collective motion in polar active matter, exemplified by the Vicsek and active Ising models. Using a simple phenomenological theory, we show the existence of an infinity of propagative solutions, describing both phase and microphase separation, that we fully characterize. We also show that the same results hold specifically in the hydrodynamic equations derived in the literature for the active Ising model and for a simplified version of the Vicsek model. We then study numerically the linear stability of these solutions. We show that stable ones constitute only a small fraction of them, which, however, includes all existing types. We further argue that, in practice, a coarsening mechanism leads towards phase-separated solutions. Finally, we construct the phase diagrams of the hydrodynamic equations proposed to qualitatively describe the Vicsek and active Ising models and connect our results to the phenomenology of the corresponding microscopic models.
BibTeX:
@article{Solon2015a,
  author = {Solon, Alexandre P. and Caussin, Jean-Baptiste and Bartolo, Denis and Chate, Hugues and Tailleur, Julien},
  title = {Pattern formation in flocking models: A hydrodynamic description},
  journal = {Physical Review E},
  year = {2015},
  volume = {92},
  number = {6},
  pages = {062111},
  doi = {10.1103/PhysRevE.92.062111}
}
  • "From Phase to Microphase Separation in Flocking Models: The Essential Role of Nonequilibrium Fluctuations"
  • A. P. Solon, H. Chate and J. Tailleur
    Physical Review Letters. 114(6):068101 (February, 2015)
Abstract: We show that the flocking transition in the Vicsek model is best understood as a liquid-gas transition, rather than an order-disorder one. The full phase separation observed in flocking models with Z(2) rotational symmetry is, however, replaced by a microphase separation leading to a smectic arrangement of traveling ordered bands. Remarkably, continuous deterministic descriptions do not account for this difference, which is only recovered at the fluctuating hydrodynamics level. Scalar and vectorial order parameters indeed produce different types of number fluctuations, which we show to be essential in selecting the inhomogeneous patterns. This highlights an unexpected role of fluctuations in the selection of flock shapes.
BibTeX:
@article{Solon2015,
  author = {Solon, Alexandre P. and Chate, Hugues and Tailleur, Julien},
  title = {From Phase to Microphase Separation in Flocking Models: The Essential Role of Nonequilibrium Fluctuations},
  journal = {Physical Review Letters},
  year = {2015},
  volume = {114},
  number = {6},
  pages = {068101},
  doi = {10.1103/PhysRevLett.114.068101}
}
  • "Friction of spheres on a rotating parabolic support"
  • A. Soulier and S. Aumaître
    American Journal of Physics. To be submitted (2015)
BibTeX:
@article{Soulier2015,
  author = {A. Soulier and S. Aumaître},
  title = {Friction of spheres on a rotating parabolic support},
  journal = {American Journal of Physics},
  year = {2015},
  volume = {To be submitted},
  note = {arxiv.org/abs/1411.0694}
}
  • "A statistical mechanics framework for the large-scale structure of turbulent von Kármán flows"
  • S. Thalabard, B. Saint-Michel, E. Herbert, F. Daviaud and B. Dubrulle
    New Journal of Physics. 17(6):063006 (2015)
Abstract: In the present paper, recent experimental results on large-scale coherent steady states observed in experimental von Kármán flows are revisited from a statistical mechanics perspective. The latter is rooted on two levels of description. We first argue that the coherent steady states may be described as the equilibrium states of well-chosen lattice models, which can be used to define global properties of von Kármán flows, such as their temperatures. The equilibrium description is then enlarged, in order to reinterpret a series of results about the stability of those steady states and their susceptibility to symmetry breaking, in the light of a deep analogy with the statistical theory of ferro-magnetism.
BibTeX:
@article{Thalabard2015,
  author = {S. Thalabard and B. Saint-Michel and E. Herbert and F. Daviaud and B. Dubrulle},
  title = {A statistical mechanics framework for the large-scale structure of turbulent von Kármán flows},
  journal = {New Journal of Physics},
  year = {2015},
  volume = {17},
  number = {6},
  pages = {063006},
  url = {http://stacks.iop.org/1367-2630/17/i=6/a=063006},
  doi = {10.1088/1367-2630/17/6/063006}
}
  • "Role of boundary conditions in helicoidal flow collimation: Consequences for the von Kármán sodium dynamo experiment"
  • J. Varela, S. Brun, B. Dubrulle and C. Nore
    Physical Review E. 92:063015 (Dec, 2015)
    American Physical Society.
BibTeX:
@article{PhysRevE.92.063015,
  author = {Varela, J. and Brun, S. and Dubrulle, B. and Nore, C.},
  title = {Role of boundary conditions in helicoidal flow collimation: Consequences for the von Kármán sodium dynamo experiment},
  journal = {Physical Review E},
  publisher = {American Physical Society},
  year = {2015},
  volume = {92},
  pages = {063015},
  url = {http://link.aps.org/doi/10.1103/PhysRevE.92.063015},
  doi = {10.1103/PhysRevE.92.063015}
}
 

Other Publication Years:

2017, 2016, 2015, 2014, 2013, 2012, Older publications (2008-2011)

 

Maj : 07/02/2017 (2611)

 

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