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One way to analyze complicated non-autonomous flows is through trying to understand their transport behavior. In a quantitative, set-oriented approach to transport and mixing, finite time coherent sets play an important role. These are…

Dynamical Systems · Mathematics 2019-07-10 Péter Koltai , D. R. Michiel Renger

We study the transport properties of nonautonomous chaotic dynamical systems over a finite time duration. We are particularly interested in those regions that remain coherent and relatively non-dispersive over finite periods of time,…

Dynamical Systems · Mathematics 2015-05-19 Gary Froyland , Naratip Santitissadeekorn , Adam Monahan

A data-driven procedure for identifying the dominant transport barriers in a time-varying flow from limited quantities of Lagrangian data is presented. Our approach partitions state space into pairs of coherent sets, which are sets of…

Fluid Dynamics · Physics 2015-07-28 Matthew O. Williams , Irina I. Rypina , Clarence W. Rowley

A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom the Poincar\'e map provides a splitting of the phase space into regions where…

Plasma Physics · Physics 2015-07-28 M. V. Falessi , F. Pegoraro , T. J. Schep

Understanding, quantifying and controlling transport and mixing processes are central in the study of fluid flows. Many different Lagrangian approaches have been proposed for detecting organizing flow structures that determine material…

Fluid Dynamics · Physics 2026-04-17 Anna Klünker , Alexandra von Kameke , Kathrin Padberg-Gehle

We present a frame-invariant method for detecting coherent structures from Lagrangian flow trajectories that can be sparse in number, as is the case in many fluid mechanics applications of practical interest. The method, based on principles…

Fluid Dynamics · Physics 2017-03-08 Kristy L. Schlueter-Kuck , John O. Dabiri

Human trajectory data is crucial in urban planning, traffic engineering, and public health. However, directly using real-world trajectory data often faces challenges such as privacy concerns, data acquisition costs, and data quality. A…

Machine Learning · Computer Science 2025-11-05 Qingyue Long , Can Rong , Tong Li , Yong Li

We explore the transport mechanisms of heat in two- and three-dimensional turbulent convection flows by means of the long-term evolution of Lagrangian coherent sets. They are obtained from the spectral clustering of trajectories of massless…

We explore the mechanisms of heat transfer in a turbulent constant heat flux-driven Rayleigh-B\'enard convection flow, which exhibits a hierarchy of flow structures from granules to supergranules. Our computational framework makes use of…

Fluid Dynamics · Physics 2023-09-15 Philipp P. Vieweg , Anna Klünker , Jörg Schumacher , Kathrin Padberg-Gehle

Coherent transport promises to be the basis for an emerging new technology. Notwithstanding, a mechanistic understanding of the fundamental principles behind optimal scattering media is still missing. Here, complex network analysis is…

Quantum Physics · Physics 2013-12-09 Stefano Mostarda , Federico Levi , Diego Prada-Gracia , Florian Mintert , Francesco Rao

We introduce the concept of a "transitory" dynamical system---one whose time-dependence is confined to a compact interval---and show how to quantify transport between two-dimensional Lagrangian coherent structures for the Hamiltonian case.…

Chaotic Dynamics · Physics 2015-03-17 B. A. Mosovsky , J. D. Meiss

We present a method for identifying the coherent structures associated with individual Lagrangian flow trajectories even where only sparse particle trajectory data is available. The method, based on techniques in spectral graph theory, uses…

Fluid Dynamics · Physics 2017-10-11 Kristy L. Schlueter-Kuck , John O. Dabiri

The detection of coherent structures is an important problem in fluid dynamics, particularly in geophysical applications. For instance, knowledge of how regions of fluid are isolated from each other allows prediction of the ultimate fate of…

Chaotic Dynamics · Physics 2013-05-28 Michael R. Allshouse , Jean-Luc Thiffeault

Understanding blood transport in cardiovascular flows is important for managing patients with cardiovascular disease. In this study, three-dimensional Lagrangian coherent structures have been extracted for the first time in both healthy…

Medical Physics · Physics 2024-01-05 Wissam Abdallah , Ahmed Darwish , Julio Garcia , Lyes Kadem

Graph Laplacians and related nonlinear mappings into low dimensional spaces have been shown to be powerful tools for organizing high dimensional data. Here we consider a data set X in which the graph associated with it changes depending on…

Classical Analysis and ODEs · Mathematics 2015-03-20 Ronald R. Coifman , Matthew J. Hirn

Deep generative models are universal tools for learning data distributions on high dimensional data spaces via a mapping to lower dimensional latent spaces. We provide a study of latent space geometries and extend and build upon previous…

Machine Learning · Computer Science 2019-02-07 Max F. Frenzel , Bogdan Teleaga , Asahi Ushio

The topic of this study lies in the intersection of two fields. One is related with analyzing transport phenomena in complicated flows.For this purpose, we use so-called coherent sets: non-dispersing, possibly moving regions in the flow's…

Numerical Analysis · Mathematics 2021-07-28 Péter Koltai , Johannes von Lindheim , Sebastian Neumayer , Gabriele Steidl

Understanding the macroscopic behavior of dynamical systems is an important tool to unravel transport mechanisms in complex flows. A decomposition of the state space into coherent sets is a popular way to reveal this essential macroscopic…

Dynamical Systems · Mathematics 2020-04-30 Gary Froyland , Péter Koltai , Martin Stahn

Urban mobility data has significant connections with economic growth and plays an essential role in various smart-city applications. However, due to privacy concerns and substantial data collection costs, fine-grained human mobility…

Social and Information Networks · Computer Science 2025-07-21 Baoshen Guo , Zhiqing Hong , Junyi Li , Shenhao Wang , Jinhua Zhao

The study of diffusion in Hamiltonian systems has been a problem of interest for a number of years. In this paper we explore the influence of self-consistency on the diffusion properties of systems described by coupled symplectic maps.…

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