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Gouiller C, Ybert C, Cottin-Bizonne C, Raynal F, Bourgoin M, Volk R. Two-dimensional numerical model of Marangoni surfers: From single swimmer to crystallization. Phys Rev E 2021; 104:064608. [PMID: 35030840 DOI: 10.1103/physreve.104.064608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/23/2021] [Indexed: 11/07/2022]
Abstract
We numerically study the dynamics of an ensemble of Marangoni surfers in a two-dimensional and unconfined space. The swimmers are modeled as Gaussian sources of surfactant generating surface tension gradients and are shown to follow the Marangoni flow filtered at their spatial scale in the lubrication regime, an unstable situation leading to spontaneous motion as soon as the Marangoni effect is intense enough. As the system is fully unconstrained, it is possible to study the various dynamical regimes from single swimmer, two-body interaction, to the many-particles case characterized by an efficient particle dispersion. We show that, although the present model is very simple, it reproduces the experimentally observed transition between a regime of dispersion by random agitation when the number of swimmers is moderate to the regime of crystallization with imperfect hexagonal lattice at high density.
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Affiliation(s)
- Clément Gouiller
- Institut Lumière Matière, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Christophe Ybert
- Institut Lumière Matière, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Cécile Cottin-Bizonne
- Institut Lumière Matière, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622 Villeurbanne, France
| | - Florence Raynal
- Laboratoire de Mécanique des Fluides et d'Acoustique, Université de Lyon, Ecole Centrale de Lyon, Université Claude Bernard Lyon 1, INSA Lyon, CNRS, F-69134 Écully, France
| | - Mickaël Bourgoin
- Laboratoire de Physique, Université de Lyon, École Normale Supérieure de Lyon, CNRS, F-69342 Lyon, France
| | - Romain Volk
- Laboratoire de Physique, Université de Lyon, École Normale Supérieure de Lyon, CNRS, F-69342 Lyon, France
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Mathai V, Calzavarini E, Brons J, Sun C, Lohse D. Microbubbles and Microparticles are Not Faithful Tracers of Turbulent Acceleration. PHYSICAL REVIEW LETTERS 2016; 117:024501. [PMID: 27447509 DOI: 10.1103/physrevlett.117.024501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Indexed: 06/06/2023]
Abstract
We report on the Lagrangian statistics of acceleration of small (sub-Kolmogorov) bubbles and tracer particles with Stokes number St≪1 in turbulent flow. At a decreasing Reynolds number, the bubble accelerations show deviations from that of tracer particles; i.e., they deviate from the Heisenberg-Yaglom prediction and show a quicker decorrelation despite their small size and minute St. Using direct numerical simulations, we show that these effects arise due the drift of these particles through the turbulent flow. We theoretically predict this gravity-driven effect for developed isotropic turbulence, with the ratio of Stokes to Froude number or equivalently the particle drift velocity governing the enhancement of acceleration variance and the reductions in correlation time and intermittency. Our predictions are in good agreement with experimental and numerical results. The present findings are relevant to a range of scenarios encompassing tiny bubbles and droplets that drift through the turbulent oceans and the atmosphere. They also question the common usage of microbubbles and microdroplets as tracers in turbulence research.
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Affiliation(s)
- Varghese Mathai
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Enrico Calzavarini
- Université de Lille, CNRS, FRE 3723, LML, Laboratoire de Mécanique de Lille, F 59000 Lille, France
| | - Jon Brons
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- Applied Mathematics Research Centre, Faculty of Engineering and Computing, Coventry University, Priory Street, Coventry CV1 5FB, United Kingdom
| | - Chao Sun
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- Center for Combustion Energy and Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China
| | - Detlef Lohse
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
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Mathai V, Prakash VN, Brons J, Sun C, Lohse D. Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence. PHYSICAL REVIEW LETTERS 2015; 115:124501. [PMID: 26430995 DOI: 10.1103/physrevlett.115.124501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 06/05/2023]
Abstract
Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multiphysics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence.
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Affiliation(s)
- Varghese Mathai
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| | - Vivek N Prakash
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
- Department of Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Jon Brons
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
| | - Chao Sun
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
- Center for Combustion Energy and Department of Thermal Engineering, Tsinghua University, 100084 Beijing, China
| | - Detlef Lohse
- Physics of Fluids Group, Faculty of Science and Technology, J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, Netherlands
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Parsa S, Voth GA. Inertial range scaling in rotations of long rods in turbulence. PHYSICAL REVIEW LETTERS 2014; 112:024501. [PMID: 24484019 DOI: 10.1103/physrevlett.112.024501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Indexed: 06/03/2023]
Abstract
We derive a scaling relationship for the mean square rotation rate of rods with lengths in the inertial range in turbulence: <p(i)p(i)> ∝ l(-4/3). We present experimental measurements of the rotational statistics of neutrally buoyant rods with lengths 2.8<l/η<72.9, and find that the measurements approach the predicted scaling. The approach to inertial range scaling is shown to be more complex than anticipated with an overshoot and approach to the scaling from above. For all rod lengths, the correlation time of the Lagrangian autocorrelation of the rotation rate scales as the turnover time of the eddies of the size of the rod. Measuring rotational dynamics of single long rods provides a new way to access the spatial structure of the flow at different length scales.
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Affiliation(s)
- Shima Parsa
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Greg A Voth
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
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Fiabane L, Zimmermann R, Volk R, Pinton JF, Bourgoin M. Clustering of finite-size particles in turbulence. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:035301. [PMID: 23030971 DOI: 10.1103/physreve.86.035301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Indexed: 06/01/2023]
Abstract
We investigate experimentally the spatial distributions of heavy and neutrally buoyant particles of finite size in a fully turbulent flow. Because their Stokes number (i.e., the ratio of the particle viscous relaxation time to a typical flow time scale) is close to unity, one may expect both classes of particles to aggregate in specific flow regions. This is not observed. Using a Voronoï analysis we show that neutrally buoyant particles sample turbulence homogeneously, whereas heavy particles do cluster. These results show that several dimensionless numbers are needed in the modeling (and understanding) of the behavior of particles entrained by turbulent motions.
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Affiliation(s)
- L Fiabane
- Laboratoire de Physique, ENS de Lyon, UMR CNRS 5672, Université de Lyon, France.
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Zimmermann R, Gasteuil Y, Bourgoin M, Volk R, Pumir A, Pinton JF. Rotational intermittency and turbulence induced lift experienced by large particles in a turbulent flow. PHYSICAL REVIEW LETTERS 2011; 106:154501. [PMID: 21568563 DOI: 10.1103/physrevlett.106.154501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Indexed: 05/30/2023]
Abstract
The motion of a large, neutrally buoyant, particle freely advected by a turbulent flow is determined experimentally. We demonstrate that both the translational and angular accelerations exhibit very wide probability distributions, a manifestation of intermittency. The orientation of the angular velocity with respect to the trajectory, as well as the translational acceleration conditioned on the spinning velocity, provides evidence of a lift force acting on the particle.
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Affiliation(s)
- Robert Zimmermann
- Laboratoire de Physique de l'École Normale Supérieure de Lyon, UMR5672, CNRS and Université de Lyon, 46 Allée d'Italie, 69007 Lyon, France
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Zimmermann R, Gasteuil Y, Bourgoin M, Volk R, Pumir A, Pinton JF. Tracking the dynamics of translation and absolute orientation of a sphere in a turbulent flow. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:033906. [PMID: 21456762 DOI: 10.1063/1.3554304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We study the six-dimensional dynamics--position and orientation--of a large sphere advected by a turbulent flow. The movement of the sphere is recorded with two high-speed cameras. Its orientation is tracked using a novel, efficient algorithm; it is based on the identification of possible orientation "candidates" at each time step, with the dynamics later obtained from maximization of a likelihood function. Analysis of the resulting linear and angular velocities and accelerations reveal a surprising intermittency for an object whose size lies in the inertial range, close to the integral scale of the underlying turbulent flow.
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Affiliation(s)
- Robert Zimmermann
- Laboratoire de Physique, CNR, UMR 5672, Ecole Normale Supérieure de Lyon, Lyon F-69007, France
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