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Recent advances enable the simultaneous computation of both attracting and repelling families of Lagrangian Coherent Structures (LCS) at the same initial or final time of interest. Obtaining LCS positions at intermediate times, however, has…

Dynamical Systems · Mathematics 2019-01-29 Daniel Karrasch , Mohammad Farazmand , George Haller

Hyperbolic Lagrangian Coherent Structures (LCSs) are locally most repelling or most attracting material surfaces in a finite-time dynamical system. To identify both types of hyperbolic LCSs at the same time instance, the standard practice…

Dynamical Systems · Mathematics 2015-06-12 Mohammad Farazmand , George Haller

Lagrangian coherent structures (LCSs) are material surfaces that shape finite-time tracer patterns in flows with arbitrary time dependence. Depending on their deformation properties, elliptic and hyperbolic LCSs have been identified from…

Dynamical Systems · Mathematics 2016-11-23 David Oettinger , George Haller

Many complex flows such as those arising from ocean plastics in geophysics or moving cells in biology are characterized by sparse and noisy trajectory datasets. We introduce techniques for identifying Lagrangian Coherent Structures (LCSs)…

Fluid Dynamics · Physics 2022-09-21 Saviz Mowlavi , Mattia Serra , Enrico Maiorino , L Mahadevan

We give an algorithmic introduction to Lagrangian coherent structures (LCSs) using a newly developed computational engine, LCS Tool. LCSs are most repelling, attracting and shearing material lines that form the centerpieces of observed…

Chaotic Dynamics · Physics 2016-04-12 K. Onu , F. Huhn , G. Haller

Lagrangian Coherent Structures (LCS) are flow features which are defined to objectively characterize complex fluid behavior over a finite time regardless of the orientation of the observer. Fluidic applications of LCS include geophysical,…

Fluid Dynamics · Physics 2023-10-18 Tanner D. Harms , Steven L. Brunton , Beverley J. McKeon

In the preliminary design of space missions it can be useful to identify regions of dynamics that drive the system's behaviour or separate qualitatively different dynamics. The Lagrangian Coherent Structure (LCS) has been widely used in the…

Earth and Planetary Astrophysics · Physics 2022-09-26 Jack Tyler , Alexander Wittig

We consider Lagrangian coherent structures (LCSs) as the boundaries of material subsets whose advective evolution is metastable under weak diffusion. For their detection, we first transform the Eulerian advection-diffusion equation to…

Dynamical Systems · Mathematics 2020-06-17 Daniel Karrasch , Johannes Keller

We develop a general theory of transport barriers for three-dimensional unsteady flows with arbitrary time-dependence. The barriers are obtained as two-dimensional Lagrangian Coherent Structures (LCSs) that create locally maximal…

Dynamical Systems · Mathematics 2015-06-16 Daniel Blazevski , George Haller

The computation of Lagrangian coherent structures (LCS) has established itself as a prominent means to reveal significant geometric structures in time-dependent vector fields. Their characterization, however, requires the selection of a…

Fluid Dynamics · Physics 2022-03-23 Zi'ang Ding , Xavier Tricoche

Lagrangian descriptors (LDs) based on the arc length of orbits previously demonstrated their utility in delineating structures governing the dynamics. Recently, a chaos indicator based on the second derivatives of the LDs, referred to as…

Chaotic Dynamics · Physics 2025-02-05 Alexandru Căliman , Jérôme Daquin , Anne-Sophie Libert

In this paper we develop new techniques for revealing geometrical structures in phase space that are valid for aperiodically time dependent dynamical systems, which we refer to as Lagrangian descriptors. These quantities are based on the…

Chaotic Dynamics · Physics 2013-08-05 Ana M. Mancho , Stephen Wiggins , Jezabel Curbelo , Carolina Mendoza

Analysis of Lagrangian Coherent Structures (LCSs) has been showed to be a valid mathematical approach to explain the formation of transport barriers in magnetized plasmas. Such LCSs, borrowed from fluid dynamics theory, can be considered as…

We describe a new method for computing coherent Lagrangian vortices in two-dimensional flows according to any of the following approaches: black-hole vortices [Haller & Beron-Vera, 2013], objective Eulerian Coherent Structures (OECSs)…

Fluid Dynamics · Physics 2020-06-23 Daniel Karrasch , Nathanael Schilling

High-speed stereo PIV-measurements have been performed in a turbulent boundary layer at Re$_{\theta}$ of 9800 in order to elucidate the coherent structures. Snapshot proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD)…

Fluid Dynamics · Physics 2017-04-14 Naseem Ali , Murat Tutkun , Raúl Bayoán Cal

In this paper, we study the convergence analysis for a robust stochastic structure-preserving Lagrangian numerical scheme in computing effective diffusivity of time-dependent chaotic flows, which are modeled by stochastic differential…

Numerical Analysis · Mathematics 2021-06-03 Zhongjian Wang , Jack Xin , Zhiwen Zhang

Semi-Lagrangian methods have traditionally been developed in the framework of hyperbolic equations, but several extensions of the Semi-Lagrangian approach to diffusion and advection--diffusion problems have been proposed recently. These…

Numerical Analysis · Mathematics 2014-05-20 L. Bonaventura , R. Ferretti

A dynamic procedure for the Lagrangian Averaged Navier-Stokes-$\alpha$ (LANS-$\alpha$) equations is developed where the variation in the parameter $\alpha$ in the direction of anisotropy is determined in a self-consistent way from data…

Fluid Dynamics · Physics 2009-11-10 Hongwu Zhao , Kamran Mohseni

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

We present TURB-Lagr, a new open database of 3d turbulent Lagrangian trajectories, obtained by Direct Numerical Simulations (DNS) of the original Navier-Stokes equations in the presence of a homogeneous and isotropic forcing. The aim is to…

Fluid Dynamics · Physics 2024-09-24 Luca Biferale , Fabio Bonaccorso , Michele Buzzicotti , Chiara Calascibetta
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