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Bourgoin M, Huisman SG. Using ray-traversal for 3D particle matching in the context of particle tracking velocimetry in fluid mechanics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:085105. [PMID: 32872904 DOI: 10.1063/5.0009357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/18/2020] [Indexed: 06/11/2023]
Abstract
An innovative method based on the traversal of rays, originating from detected particles, through a three-dimensional grid of voxels is presented. The methodology has the main advantage that the outcome of the method is independent of the order of the input; the order of the cameras and the order of the rays presented as input to the algorithm do not influence the outcome. The algorithm finds matches in decreasing value of match quality, ensuring that globally best matches are matched before worse matches. The time complexity of the algorithm is found to scale efficiently with the number of cameras and particles. A variety of show-cases are given to exemplify the algorithm for different geometries and different numbers of cameras. The method is designed for the tracking of tracer or inertial particles in fluid mechanics, for which the particle size generally ranges from O (μm)-O (cm). The method, however, does not impose a size limit on the particles.
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Affiliation(s)
- Mickaël Bourgoin
- Univ Lyon, École normale supérieure de Lyon, Univ Claude Bernard Lyon 1, C.N.R.S., Laboratoire de Physique, F-69342 Lyon, France
| | - Sander G Huisman
- Univ Lyon, École normale supérieure de Lyon, Univ Claude Bernard Lyon 1, C.N.R.S., Laboratoire de Physique, F-69342 Lyon, France
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Wang Z, Mathai V, Sun C. Self-sustained biphasic catalytic particle turbulence. Nat Commun 2019; 10:3333. [PMID: 31350393 PMCID: PMC6659658 DOI: 10.1038/s41467-019-11221-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/01/2019] [Indexed: 11/30/2022] Open
Abstract
Turbulence is known for its ability to vigorously mix fluid and transport heat. Despite over a century of research for enhancing heat transport, few have exceeded the inherent limits posed by turbulent-mixing. Here we have conceptualized a kind of "active particle" turbulence, which far exceeds the limits of classical thermal turbulence. By adding a minute concentration (ϕv ∼ 1%) of a heavy liquid (hydrofluoroether) to a water-based turbulent convection system, a remarkably efficient biphasic dynamics is born, which supersedes turbulent heat transport by up to 500%. The system operates on a self-sustained dynamically equilibrated cycle of a "catalyst-like" species, and exploits several heat-carrier agents including pseudo-turbulence, latent heat and bidirectional wake capture. We find that the heat transfer enhancement is dominated by the kinematics of the active elements and their induced-agitation. The present finding opens the door towards the establishment of tunable, ultra-high efficiency heat transfer/mixing systems.
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Affiliation(s)
- Ziqi Wang
- Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, 100084, Beijing, China
| | - Varghese Mathai
- School of Engineering, Brown University, Providence, RI, 02912, USA
| | - Chao Sun
- Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, 100084, Beijing, China.
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Mathai V, Zhu X, Sun C, Lohse D. Flutter to tumble transition of buoyant spheres triggered by rotational inertia changes. Nat Commun 2018; 9:1792. [PMID: 29728557 PMCID: PMC5935758 DOI: 10.1038/s41467-018-04177-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/08/2018] [Indexed: 11/12/2022] Open
Abstract
Heavy particles sink straight in water, while buoyant bubbles and spheres may zigzag or spiral as they rise. The precise conditions that trigger such path-instabilities are still not completely understood. For a buoyant rising sphere, two parameters are believed to govern the development of unsteady dynamics: the particle's density relative to the fluid, and its Galileo number. Consequently, with these parameters specified, the opportunities for variation in particle dynamics appear limited. In contrast to this picture, here we demonstrate that vigorous path-oscillations can be triggered by modulating a spherical particle's moment of inertia (MoI). For a buoyant sphere rising in a turbulent flow, MoI reduction triggers a tumble-flutter transition, while in quiescent liquid, it induces a modification of the sphere wake resulting in large-amplitude path-oscillations. The present finding opens the door for control of particle path- and wake-instabilities, with potential for enhanced mixing and heat transfer in particle-laden and dispersed multiphase environments.
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Affiliation(s)
- Varghese Mathai
- Physics of Fluids Group and Max Planck Center for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands
| | - Xiaojue Zhu
- Physics of Fluids Group and Max Planck Center for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands
| | - Chao Sun
- Physics of Fluids Group and Max Planck Center for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
- Center for Combustion Energy and the Department of Energy and Power Engineering, Tsinghua University, 100084, Beijing, China.
| | - Detlef Lohse
- Physics of Fluids Group and Max Planck Center for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
- Center for Combustion Energy and the Department of Energy and Power Engineering, Tsinghua University, 100084, Beijing, China.
- Max Planck Institute for Dynamics and Self-Organization, 37077, Göttingen, Germany.
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