[HTML][HTML] A geometric heat-flow theory of Lagrangian coherent structures

D Karrasch, J Keller - Journal of Nonlinear Science, 2020 - Springer
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 …

Definition and properties of Lagrangian coherent structures from finite-time Lyapunov exponents in two-dimensional aperiodic flows

SC Shadden, F Lekien, JE Marsden - Physica D: Nonlinear Phenomena, 2005 - Elsevier
This paper develops the theory and computation of Lagrangian Coherent Structures (LCS),
which are defined as ridges of Finite-Time Lyapunov Exponent (FTLE) fields. These ridges …

Hyperbolic and elliptic transport barriers in three-dimensional unsteady flows

D Blazevski, G Haller - Physica D: Nonlinear Phenomena, 2014 - Elsevier
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 …

Understanding the geometry of transport: Diffusion maps for Lagrangian trajectory data unravel coherent sets

R Banisch, P Koltai - Chaos: An Interdisciplinary Journal of Nonlinear …, 2017 - pubs.aip.org
One aspect of the coexistence of regular structures and chaos in many dynamical systems is
the emergence of coherent sets: If we place a large number of passive tracers in a coherent …

A variational theory of hyperbolic Lagrangian coherent structures

G Haller - Physica D: Nonlinear Phenomena, 2011 - Elsevier
We develop a mathematical theory that clarifies the relationship between observable
Lagrangian Coherent Structures (LCSs) and invariants of the Cauchy–Green strain tensor …

Formation of coherent structures by fluid inertia in three-dimensional laminar flows

Z Pouransari, MFM Speetjens… - Journal of fluid …, 2010 - cambridge.org
Mixing under laminar flow conditions is key to a wide variety of industrial fluid systems of
size extending from micrometres to metres. Profound insight into three-dimensional laminar …

Sensitivity of Lagrangian coherent structure identification to flow field resolution and random errors

AB Olcay, TS Pottebaum, PS Krueger - Chaos: An Interdisciplinary …, 2010 - pubs.aip.org
The effect of spatial and temporal resolutions and random errors on identification of
Lagrangian coherent structures (LCSs) from Eulerian velocity fields is evaluated using two …

[图书][B] Turbulence, coherent structures, dynamical systems and symmetry

P Holmes - 2012 - books.google.com
Turbulence pervades our world, from weather patterns to the air entering our lungs. This
book describes methods that reveal its structures and dynamics. Building on the existence of …

Objective Eulerian coherent structures

M Serra, G Haller - Chaos: An Interdisciplinary Journal of Nonlinear …, 2016 - pubs.aip.org
Short-term variability in material structures is often seen as significant in unsteady flows.
Such variability is of prime interest in many fields ranging from flow control to environmental …

Finding finite-time invariant manifolds in two-dimensional velocity fields

G Haller - Chaos: An Interdisciplinary Journal of Nonlinear …, 2000 - pubs.aip.org
For two-dimensional velocity fields defined on finite time intervals, we derive an analytic
condition that can be used to determine numerically the location of uniformly hyperbolic …