Article
Physics, Multidisciplinary
Kuniyasu Saitoh, Takeshi Kawasaki
Summary: We investigated the characteristics of two-dimensional dense granular flows using molecular dynamics simulations. Our results show that the shear-induced diffusion of granular particles exhibits different behaviors at different time scales, and is also influenced by the contact damping model.
FRONTIERS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Kasra Farain, Daniel Bonn
Summary: The question of when dense granular materials start to flow under stress has not been resolved. A simple equation based on frictional aging of the granular packing is developed and tested, resulting in a nonmonotonic stress-strain relation independent of shear rate. This relation helps understand the quasistatic deformations and solid-to-liquid transition of aging granular media. It also explains the flow history dependence of mechanical properties and sensitivity to initial preparation of granular media.
PHYSICAL REVIEW LETTERS
(2023)
Article
Mechanics
Peter Varun Dsouza, Prabhu R. Nott
Summary: Granular materials exhibit unique features such as dilatancy and large-scale secondary flow driven by a combination of shear and gravity. The height at which the material is filled in a primary flow determines both the shape of the shearing region and the form of the secondary flow, indicating a close coupling between the two phenomena. Unlike fluid instabilities driven by inertia, the secondary flow in granular materials occurs at low shear rates and is an integral part of the kinematic response.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Giorgos Kanellopoulos, Dimitrios Razis, Ko van der Weele
Summary: In this paper, jumps in granular chute flow are obtained as continuous solutions of the Saint-Venant equations. The internal structure of these jumps is elucidated through a dynamical systems approach, showing trajectories organized around the stable/unstable manifold of a fixed point. An analytic approximate expression for jump length is derived, with numerical experiments confirming jump stability.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Ishan Srivastava, Leonardo E. Silbert, Gary S. Grest, Jeremy B. Lechman
Summary: This study investigates the flow of dense granular materials under external shear stress and pressure using discrete element method simulations, proposing a rheological model to describe the two types of flow. The simulations show viscometric behavior with non-negligible first and second normal stress differences, highlighting the role of contact fabric tensor and strain rate tensor in determining normal stress differences.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
T. Trewhela, C. Ancey, J. M. N. T. Gray
Summary: Particles of differing sizes are prone to segregation in shear driven flows, affecting industrial processes and hazardous geophysical mass flows. Refractive-index matched oscillatory shear-cell experiments have identified a unifying scaling law for segregation velocity in extreme cases.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Meng Liu, Christoph R. Muller
Summary: The lift force model for intruders in dense, granular shear flows takes into account granular temperature, pressure differences, and density differences between the intruder and the bed particles. The model accurately predicts and explains the behavior of intruders in shear flows.
Article
Engineering, Multidisciplinary
Fuzhen Chen, Tengda Shi, Hong Yan, Hongfu Qiang
Summary: A new constitutive model was designed in this study to consider the cohesion in dense granular media. The model includes a linear elastic-plastic constitutive relationship for the solid-like phase and a viscoplastic constitutive model for the liquid-like phase. Smoothed particle hydrodynamics method was used to discretely solve the new model, and its effectiveness was verified through various cases.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Chemical
Wenguang Nan, Mehrdad Pasha, Mojtaba Ghadiri
Summary: Understanding the rheological behavior of fully three-dimensional and non-uniform particle flow is crucial. By analyzing the resistance exhibited by a granular bed as a rotating impeller penetrates into it, the rheological characteristics of the bed can be deduced. The relationship between shear strain rate, inertia number, and bulk friction coefficient differs between spherical and rodlike particles.
Article
Multidisciplinary Sciences
Dmitry Puzyrev, David Fischer, Kirsten Harth, Torsten Trittel, Raul Cruz Hidalgo, Eric Falcon, Martial Noirhomme, Eric Opsomer, Nicolas Vandewalle, Yves Garrabos, Carole Lecoutre, Fabien Palencia, Ralf Stannarius
Summary: Studying the dynamics of granular multiparticle ensembles requires optical analysis methods. Numerical simulations similar to experiments can be used to validate the reliability of analysis methods. This approach not only confirms the accuracy of simulations, but also tests the applicability of visual analysis.
SCIENTIFIC REPORTS
(2021)
Editorial Material
Chemistry, Physical
Kwok Soon Wun, In Young Hwang, Matthew Wook Chang
Summary: The prototypical biocomposite block, made up of a blend of bacteria, fungi and feedstock, can be assembled into human-sized living structures with self-healing and environmental sensing capabilities.
Article
Materials Science, Ceramics
Danqi Yin, Kuo-Hao Lee, Collin J. Wilkinson, Yongjian Yang, Karan Doss, John C. Mauro
Summary: Dynamical heterogeneities in glass-forming systems result in spatiotemporal fluctuations and a wide distribution of relaxation rates. This study investigates the dominant factors governing dynamical heterogeneities in borosilicate glass. Molecular dynamics simulations using the isoconfigurational ensemble method were performed to study the dynamical heterogeneities of two alkali-(alumino)borosilicate glasses. It was found that alkali ions exhibit high dynamical propensities in local spatial regions. The number of bridging oxygens for boron and silicon does not monotonically correlate with their corresponding dynamical propensities.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Physics, Fluids & Plasmas
M. P. van Schrojenstein Lantman, K. van der Vaart, S. Luding, A. R. Thornton
Summary: The study provides a new micromechanical analysis that connects the microscale contact behavior to the macroscopic granular buoyancy force, supporting the existing Voronoi approximation for calculation of the buoyancy force. The findings also substantiate the decomposition of the net force into buoyancy and segregation lift, ultimately aiding the development of new models for size segregation by linking micro and macro behavior closely.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Physics, Multidisciplinary
Matthew Macaulay, Pierre Rognon
Summary: This study examines the distribution of contact forces in dense granular flows and finds that higher magnitude contact forces exist in faster flows with stiffer grains. A proposed physical mechanism explains this rate-dependent force transmission, establishing a relationship between contact forces and grain velocities. This analysis provides a starting point for unifying a range of continuum models based on either contact forces or grain velocities.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Chemical
Chaofeng Zhang, Xiaoyan Ye
Summary: This paper simulates the impact of a projectile on a granular target using the discrete element method and investigates the resistance force and rheological properties. The study identifies three distinct regions of resistance force and proposes a force model related to penetration depth and angle. Additionally, a rheology model based on packing fraction and inertial number is developed.
Article
Biology
Sophia Karpenko, Sebastien Wolf, Julie Lafaye, Guillaume Le Goc, Thomas Panier, Volker Bormuth, Raphael Candelier, Georges Debregeas
Article
Physics, Multidisciplinary
Mathias Casiulis, Marco Tarzia, Leticia F. Cugliandolo, Olivier Dauchot
PHYSICAL REVIEW LETTERS
(2020)
Article
Biochemical Research Methods
Benjamin Gallois, Raphael Candelier
Summary: FastTrack is a versatile and fast tracking software that is particularly suitable for animal and cell tracking in two dimensions. It introduces a new measure called the probability of incursions and leverages an iterative algorithm to optimize tracking parameters. Benchmark tests show that FastTrack is significantly faster than state-of-the-art tracking algorithms while maintaining comparable tracking accuracy.
PLOS COMPUTATIONAL BIOLOGY
(2021)
Article
Biology
Guillaume Le Goc, Julie Lafaye, Sophia Karpenko, Volker Bormuth, Raphael Candelier, Georges Debregeas
Summary: Analyzing the spontaneous exploration of zebrafish larvae revealed that temperature impacts locomotor patterns but does not change internal variability. The study showed that animals probe the behavioral space through slow diffusive-like exploration. Bath temperature restricts sampling statistics, leading to basic thermophobic behavior in the animal.
Article
Biochemistry & Molecular Biology
Margherita Zaupa, Seyedeh Maryam Alavi Naini, Maroun Abi Younes, Erika Bullier, Erik R. Duboue, Herve Le Corronc, Hedi Soula, Sebastien Wolf, Raphael Candelier, Pascal Legendre, Marnie E. Halpern, Jean-Marie Mangin, Elim Hong
Summary: The study reveals how animals' survival depends on the correct selection of an appropriate behavioral response to external stimuli through the competition among neural circuits. The evolutionarily conserved forebrain to midbrain habenulo-interpeduncular nucleus (Hb-IPN) pathway consists of cholinergic and non-cholinergic neurons that mediate different aversive behaviors. The findings demonstrate a hardwired mode of competition at the terminals of two excitatory neuronal populations, providing a physiological framework to explore the relationship between different aversive responses.
News Item
Physics, Multidisciplinary
Olivier Dauchot
Article
Physics, Multidisciplinary
Rahul N. Chacko, Francois P. Landes, Giulio Biroli, Olivier Dauchot, Andrea J. Liu, David R. Reichman
Summary: As liquids approach the glass transition temperature, dynamical heterogeneity becomes a crucial universal feature of their behavior. Dynamic facilitation, where local motion triggers further motion nearby, is a major player in this phenomenon. Long-ranged, elastically mediated facilitation appears below the mode coupling temperature, in addition to the short-range component present at all temperatures. These results suggest strong connections between the supercooled liquid and glass states, laying the groundwork for a deeper understanding of dynamical heterogeneity in glassy systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Juliane U. Klamser, Olivier Dauchot, Julien Tailleur
Summary: The study reveals that for kinetic Monte Carlo descriptions of active particles, a continuous-time limit is ill-defined when relying solely on persistent, active steps. However, mixing passive steps with active ones can lead to a well-defined continuous-time limit. New KMC algorithms are proposed to obtain dynamics of active Ornstein-Uhlenbeck, active Brownian, and run-and-tumble particles.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
P. Baconnier, D. Shohat, C. Hernandez Lopez, C. Coulais, V Demery, G. During, O. Dauchot
Summary: This study introduces a minimal realization of an active elastic solid and characterizes the emergence of selective and collective actuation resulting from the interplay between activity and elasticity. The bifurcation scenario and selection mechanism by which the collective actuation takes place are unveiled through experiments and theoretical analyses.
Article
Physics, Multidisciplinary
Pavan V. Kashyap, Yohann Duguet, Olivier Dauchot
Summary: The formation of laminar-turbulent pattern is a distinctive feature of the intermittency regime in subcritical plane shear flows. Through extensive numerical simulations, it is shown that the pattern arises from a spatial modulation of turbulent flow due to linear instability. By sampling the linear response of turbulent field to a temporal impulse, the dispersion relation is constructed from ensemble-averaged relaxation rates. As the instability threshold is approached, the relaxation rate of the least damped modes eventually reaches zero.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Paul Baconnier, Dor Shohat, Olivier Dauchot
Summary: The recent finding of collective actuation in active solids provides new possibilities for the design of multifunctional materials and the understanding of biological systems. The study combines experimental and numerical approaches to reveal a new form of collective actuation and highlight the role of mechanical tension in transitioning between different actuation regimes. The presence of hysteresis emphasizes the nontrivial selectivity of collective actuations.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Nuno A. M. Araujo, Liesbeth M. C. Janssen, Thomas Barois, Guido Boffetta, Itai Cohen, Alessandro Corbetta, Olivier Dauchot, Marjolein Dijkstra, William M. Durham, Audrey Dussutour, Simon Garnier, Hanneke Gelderblom, Ramin Golestanian, Lucio Isa, Gijsje H. Koenderink, Hartmut Loewen, Ralf Metzler, Marco Polin, C. Patrick Royall, Andela Saric, Anupam Sengupta, Cecile Sykes, Vito Trianni, Idan Tuval, Nicolas Vogel, Julia M. Yeomans, Iker Zuriguel, Alvaro Marin, Giorgio Volpe
Summary: Self-organisation is the spontaneous emergence of spatio-temporal structures and patterns from the interaction of smaller individual units. Confinement can mediate and control self-organisation by limiting the translational and rotational degrees of freedom, acting as a catalyst or inhibitor. By constraining the self-organisation process in soft-matter systems, confinement can actively steer the emergence or suppression of collective phenomena in space and time.
Article
Robotics
Matan Yah Ben Zion, Jeremy Fersula, Nicolas Bredeche, Olivier Dauchot
Summary: We present a mechanical design rule that enables robots to operate in a collision-dominated environment. By encoding a reorientation response to external forces in a three-dimensional printed exoskeleton, we enhance the motility and stability of individual robots and leverage steric interactions for collective behavior. This mechanical layer adds to the robot's sense-act cycle at the swarm level and promotes information flow for online distributed learning.
Article
Physics, Fluids & Plasmas
Caleb J. Anderson, Guillaume Briand, Olivier Dauchot, Alberto Fernandez-Nieves
Summary: The configurations of polymers in out-of-equilibrium baths have implications in biological systems. Comparing with thermal-like baths, active baths affect the polymer's Kuhn length and lead to more prominent bends in their configurations.
Article
Chemistry, Physical
Charlotte de Blois, Vincent Bertin, Saori Suda, Masatoshi Ichikawa, Mathilde Reyssat, Olivier Dauchot
Summary: The behavior of self-propelled water-in-oil droplets in capillaries of different cross-sections was experimentally investigated. It was found that the velocity of the droplet decreases with increasing confinement in straight capillaries, but even very long droplets can still swim at very high confinement. In stretched circular capillaries, the non-uniform thickness of the lubrication layer around the droplet leads to neck formation and eventual spontaneous splitting events for large enough confinement, highlighting the critical role of the droplet's interface activity under confinement.
