Article
Mechanics
C. Tregaskis, C. G. Johnson, X. Cui, J. M. N. T. Gray
Summary: The interaction between a rapid granular avalanche and a blunt obstacle is qualitatively altered when the incline of the slope changes from smooth to rough. On a rough incline, the friction between the grains and the incline allows for both rapid and slow avalanches. Rapid flows are diverted by the formation of a bow shock and a static dead zone upstream of the obstacle, while slow flows smoothly pass around the obstacle. Numerical simulations capture this behavior and provide insights for geophysical mass flows and snow avalanches.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Wenjin Han, Dengming Wang, Yisong Wu
Summary: This study numerically investigates the flow of non-spherical particles down an inclined plane using the discrete element method, focusing on the effect of particle non-convexity on flow properties. A phase diagram of flow states is presented, followed by an analysis of flow properties and development of rheological models for steady flow of non-convex particles on a rough inclined plane. This method of constructing rheological models for non-spherical particles is expected to be useful for studying dense flows with complex shapes and conditions.
Article
Mechanics
Wladimir Sarlin, Cyprien Morize, Alban Sauret, Philippe Gondret
Summary: The study experimentally characterizes waves generated by the gravity-driven collapse of a dry granular column into water, identifying three nonlinear wave regimes. This contributes to a better understanding of the rich hydrodynamics of the generated waves, with practical applications for coastal risk assessment.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Chemical
S. H. Chou, S. J. Yang, S. S. Hsiau
Summary: The occurrence of slope disasters is influenced by factors such as terrain slope, size and amount of soil and rock particles, and heavy rain. This study used experiments to investigate the erosion and deposition behavior of granular collapse flows based on the particle size and initial aspect ratio of granular beds. The results showed that increasing the particle size of the column bed led to a larger erosion area, while the particle size of the erodible bed had a minimal effect. The final erosion area slightly increased with an increase in the initial aspect ratio, but decreased when a larger particle size of the erodible bed was present. However, when the particle size of the erodible bed was smaller than that of the column bed, the final erosion area significantly increased with an increase in the aspect ratio.
Article
Mechanics
Manon Robbe-Saule, Cyprien Morize, Robin Henaff, Yann Bertho, Alban Sauret, Philippe Gondret
Summary: The study investigates the generation of a tsunami wave by an aerial landslide through model laboratory experiments. It is found that the collective entry of granular material into water governs the wave generation process, with the amplitude of the wave linearly scaling with the water height. The density of the falling grains has a negligible influence on the wave amplitude, suggesting that the volume of grains entering the water is the relevant parameter in wave generation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Guibin Zhang, Jianyun Chen, Youting Qi, Jing Li, Qiang Xu
Summary: An advanced model is developed to simulate the motion of granular landslides and resulting tsunami waves. The model establishes governing equations for fluid and granular phases, and adopts relevant models to calculate physical properties and force effects. The accuracy and stability of numerical calculation are improved by artificial diffusion and particle shifting technique.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Mechanics
Souradip Chattopadhyay, Anandamoy Mukhopadhyay
Summary: In this study, the nonlinear stability of a thin viscoelastic film under the influence of gravity, Coriolis and centrifugal forces was investigated. Through two-step analysis, the impact of viscoelastic parameter and Taylor number on flow stability was revealed. The findings were validated through direct numerical simulations, showing good agreement between analytical predictions and numerical results.
Article
Engineering, Chemical
Ravindra S. Ghodake, Pankaj Doshi, Ashish Orpe
Summary: This study investigates the gravity driven flow of millimetric granular material coated with micron-sized lubricant particles. The experimental results show a non-monotonic behavior in the volumetric flow rate of the particles with increasing lubricant concentration. This behavior is attributed to the reduction of inter-particle friction caused by the adherence of lubricant particles to the granular surface, as well as the damping effect on inter-particle collision at higher lubricant concentrations.
Article
Mechanics
Arghya Samanta
Summary: This study deciphers the linear stability of a shear-imposed viscous liquid flowing down a vibrating inclined plane and reveals different types of instabilities depending on the amplitude of forcing and shear stress. The presence of shear stress can either intensify or weaken certain instabilities, such as the subharmonic and harmonic resonances. Additionally, new instabilities, like the shear instability, can arise under specific conditions. The results highlight the complex interplay between different factors affecting the stability of the flow system.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mathematics, Applied
Firas Dhaouadi, Sergey Gavrilyuk, Jean -Paul Vila
Summary: This study presents a family of relaxation models for thin films flows, considering both viscosity and surface tension effects. The dissipationless part of the system is approximated using a first-order hyperbolic approach, where an augmented Lagrangian method and hyperbolic closure equations are employed. The viscous terms can be directly included in the system or represented by an approximate algebraic source term, and the extension to a classical nonlinear surface tension model is also discussed. Numerical results are compared with experimental data and reference solutions.
APPLIED MATHEMATICS AND COMPUTATION
(2022)
Article
Mechanics
Subham Pal, Arghya Samanta
Summary: This study conducted a linear stability analysis of a surfactant-laden viscoelastic liquid flowing down a slippery inclined plane. The results showed that the viscoelastic coefficient has a destabilizing effect on the primary instability induced by the surface mode in the long-wave regime, but has a stabilizing effect when the Reynolds number is far from the onset of instability. Additionally, a shear mode was identified at high Reynolds numbers and low inclination angles, which significantly accelerated the transition from stable to unstable flow configurations for the viscoelastic liquid.
Article
Mechanics
D. Mounkaila Noma, S. Dagois-Bohy, S. Millet, V Botton, D. Henry, H. Ben Hadid
Summary: The primary instability of a visco-plastic film flow down an inclined plane was experimentally studied. Controlled perturbations were used to generate surface waves, and the downstream evolution was observed to obtain growth rates, cutoff frequencies, and critical Reynolds and Bingham numbers. The experimental stability map was well described by the pseudo-plug model, but a more accurate model is needed for dispersion effects.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Souradip Chattopadhyay
Summary: The study examines the stability of a thin viscous Newtonian fluid with broken time-reversal-symmetry draining down a slippery inclined plane. The odd viscosity coefficient introduces new characteristics in fluid flow and modifies the pressure gradient. The presence of odd viscosity impacts the flow system parameters and influences the stability of the fluid, with larger odd viscosity leading to higher critical Reynolds number and higher slip length promoting instability.
Article
Physics, Fluids & Plasmas
Brennan Sprinkle, Sam Wilken, Shake Karapetyan, Michio Tanaka, Zhe Chen, Joseph R. Cruise, Blaise Delmotte, Michelle M. Driscoll, Paul Chaikin, Aleksandar Donev
Summary: The study investigates the driven collective dynamics of a colloidal monolayer sedimenting down an inclined plane, leading to the formation of a triangular inhomogeneous density profile with a traveling density shock at the leading front. Through experimental measurements and particle-based computer simulations, it is found that the Burgers equation can model the density profile along the sedimentation direction remarkably well, with a modest improvement when accounting for the sublinear dependence of the collective sedimentation velocity on density.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mechanics
Subham Pal, Arghya Samanta
Summary: The linear stability analysis of a contaminated viscoelastic liquid flowing down an inclined plane with imposed shear stress showed that as the Weissenberg number increases, the critical Reynolds number for the interface mode decreases while the stable region in the finite wavenumber regime expands. Additionally, the presence of insoluble surfactant reduces the unstable domain induced by the interface mode, while applied shear stress enhances it.
Article
Chemistry, Physical
Yage Zhang, Chentianyi Yang, Shuai Yuan, Xiaoxue Yao, Youchuang Chao, Yang Cao, Qingchun Song, Alban Sauret, Bernard P. Binks, Ho Cheung Shum
Summary: The experiment demonstrated the influence of different particle coverings on liquid marbles in the electrocoalescence process, resulting in four different morphologies. Small particles showed little resistance to coalescence, while marbles coated by large particles demonstrated a viscous-like behavior.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Mechanics
Deok-Hoon Jeong, Michael Ka Ho Lee, Virgile Thievenaz, Martin Z. Bazant, Alban Sauret
Summary: Dip coating is a process of coating a substrate with a thin liquid layer by withdrawing it from a bath. The presence of particles introduces new length scales and affects the thickness of the coating film. This study investigates the dip coating of suspensions with a bimodal size distribution of particles. It is found that the effective viscosity approach is still valid when the coating film is thicker than the diameter of the largest particles. A model is proposed to predict the probability of entraining the particles in the liquid film.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Chemistry, Physical
Brian Dincau, Connor Tang, Emilie Dressaire, Alban Sauret
Summary: This study experimentally investigates the influence of pulsatile pressure-driven flows on clogging in microfluidic channels. The results show that pulsatile flows can delay clogging, but the effect diminishes at lower frequencies. This study demonstrates the potential of pulsatile flows in mitigating clogging.
Correction
Chemistry, Physical
Yage Zhang, Chentianyi Yang, Shuai Yuan, Xiaoxue Yao, Youchuang Chao, Yang Cao, Qingchun Song, Alban Sauret, Bernard P. Binks, Ho Cheung Shum
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Multidisciplinary Sciences
Virgile Thievenaz, Alban Sauret
Summary: At large scales, particulate suspensions flow like homogeneous viscous liquids, but at the particle scale, the role of local heterogeneity brought by the particles cannot be neglected. The volume fraction also matters, as particulate effects can be present in dense suspensions across distances much larger than the particle diameter. Therefore, the behavior of a suspension depends on the scale at which it is observed.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Fluids & Plasmas
Ram Sudhir Sharma, Mingze Gong, Sivar Azadi, Adrien Gans, Philippe Gondret, Alban Sauret
Summary: This paper investigates the effect of interparticle cohesive forces on the erosion of a flat granular bed by an impinging turbulent jet in air. The experiments show that the cohesive forces influence the erosion threshold and can be explained by a cohesive Shields number. Additionally, the cohesive forces also affect the shape of the resulting crater, the transport of grains, and the local erosion process.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Multidisciplinary Sciences
Robert Kostynick, Hadis Matinpour, Shravan Pradeep, Sarah Haber, Alban Sauret, Eckart Meiburg, Thomas Dunne, Paulo Arratia, Douglas Jerolmack
Summary: Debris flows, which are dense and fast-moving suspensions of soil and water, pose a threat to lives and infrastructure. This study examines the composition and flow behavior of source materials that formed post-wildfire debris flows in Montecito, CA in 2018. The results show that shear viscosity and yield stress are influenced by the distance from jamming, and by rescaling the shear and viscous stresses, the data collapses onto a flow curve indicative of a Bingham plastic fluid. These findings suggest that determining the jamming fraction can significantly improve flow models for geophysical suspensions such as debris flows.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Fluids & Plasmas
Wladimir Sarlin, Cyprien Morize, Alban Sauret, Philippe Gondret
Summary: This article presents a predictive model for the amplitude of impulse waves generated by the collapse of a granular column into a water layer. The model is successfully compared to laboratory experiments and captures the influence of initial parameters. Furthermore, the role of two key dimensionless numbers in wave generation is rationalized.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Computer Science, Interdisciplinary Applications
Elyce Bayat, Raphael Egan, Daniil Bochkov, Alban Sauret, Frederic Gibou
Summary: In this paper, a numerical method is presented for solving the interfacial growth problem governed by the Stefan model coupled with incompressible fluid flow. The method employs level-set methods, adaptive quadtree grids, and a pressure-free projection method to track the interface and solve the incompressible Navier-Stokes equations. The method is verified and validated through numerical tests and computational studies, providing new insights into interface morphologies and heat transfer time evolution.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
A. Gans, A. Abramian, P. -y. Lagree, M. Gong, A. Sauret, O. Pouliquen, M. Nicolas
Summary: The collapse of a quasi-two-dimensional column of cohesive granular media is investigated experimentally and numerically in the framework of a continuum model. The role of cohesion on the stability of the column, the mode of failure, the flow dynamics and the geometry of the final deposit are studied. The continuum model captures the main features observed experimentally.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Chemistry, Physical
Deok-Hoon Jeong, Langqi Xing, Michael Ka Ho Lee, Nathan Vani, Alban Sauret
Summary: The dip coating of suspensions made of monodisperse non-Brownian spherical particles dispersed in a Newtonian fluid leads to different coating regimes depending on the ratio of the particle diameter to the thickness of the film entrained on the substrate. In the case of anisotropic particles, in particular fibers, the smallest characteristic dimension will control the entrainment of the particle. Furthermore, it is possible to control the orientation of the anisotropic particles depending on the substrate geometry. The Landau-Levich-Derjaguin law is recovered for more concentrated suspension by introducing an effective capillary number accounting for the change in viscosity.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
Joanne Steiner, Cyprien Morize, Ivan Delbende, Alban Sauret, Philippe Gondret
Summary: In this article, the time evolution of vortex rings generated by the translation of a rigid disk in a fluid is investigated. The startup vortex ring and its dynamics are characterized experimentally and numerically. The observed scaling laws of the maximum radius and circulation of the vortex ring are captured by a modified theoretical model.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Chemistry, Physical
D-H Jeong, L. Xing, J-B Boutin, A. Sauret
Summary: This study investigates the coating process of a suspension of particles on the walls of a capillary tube. The results show that the coating mechanism is influenced by the particle size, volume fraction of the suspension, and translation speed of the plug. Additionally, the study reveals that a shear-induced migration mechanism can modify the thickness and composition of the deposited film.
Article
Chemistry, Physical
Nathan Vani, Sacha Escudier, Alban Sauret
Summary: This study investigates the mechanism of particle clogging in confined systems, focusing on bridging clogging. Experimental characterization of particulate suspensions flow through millifluidic devices at different concentrations was conducted, and the influence of solid fraction on clogging probability was discussed.
Article
Chemistry, Physical
Sreeram Rajesh, Virgile Thievenaz, Alban Sauret
Summary: This study investigates the transition from Newtonian to viscoelastic behavior during the pinch-off process of droplets in dilute polymer solutions and explores its connection to the coil-stretch transition in polymer chains. The detachment of a droplet from a nozzle leads to the formation of a liquid neck, causing a localized increase in stress. In polymer solutions, this stress gradually unwinds the polymer chains until the viscosity increases significantly, resulting in a slowdown of the thinning process. This threshold for viscoelastic behavior corresponds to a macroscopic strain rate. The study characterizes the variations of this transition with respect to polymer concentration, molar weight, solvent viscosity, and nozzle size. Empirical scaling laws are provided for these variations. The thinning dynamics at the transition are also analyzed, revealing a self-similar behavior controlled by a characteristic time which is different and shorter than the relaxation time of the polymer.
