---
OA_type: closed access
_id: '19035'
abstract:
- lang: eng
  text: 'Lagrangian coherent structures (LCSs) are widely recognized as playing a
    significant role in turbulence dynamics since they can control the transport of
    mass, momentum or heat. However, the methods used to identify these structures
    are often based on ambiguous definitions and arbitrary thresholding. While LCSs
    theory provides precise and frame-indifferent mathematical definitions of coherent
    structures, some of the commonly used extraction algorithms employed in the literature
    are still case-specific and involve user-defined parameters. In this study, we
    present a new, unsupervised extraction algorithm that enables the extraction of
    rotational LCSs based on Lagrangian average vorticity deviation from an arbitrary
    3D velocity field. The algorithm utilizes two alternative methods for the identification
    of the LCS core (ridge): an unsupervised clustering method and a streamline-based
    method. In a subsequent step, the ridge curve is parametrized through a pruning
    procedure of minimum spanning tree graphs. To assess the effectiveness of the
    algorithm, we test it on two cases: (i) direct numerical simulations of forced
    homogeneous and isotropic turbulence and (ii) three-dimensional Particle Tracking
    Velocimetry experiments of a turbulent gravity current.'
acknowledgement: M.M.N.H. and M.H. acknowledge financial support from SNSF grant number
  200727. M.H. and S.B. acknowledge financial support from the DFG priority program
  SPP 1881 Turbulent Superstructures under Grant No. HO5519/1-2.
article_number: '106558'
article_processing_charge: No
article_type: original
author:
- first_name: Marius M.
  full_name: Neamtu-Halic, Marius M.
  last_name: Neamtu-Halic
- first_name: Stefano
  full_name: Brizzolara, Stefano
  id: 4bbe33b8-c59a-11ee-a1af-fa33d1ac42c4
  last_name: Brizzolara
- first_name: George
  full_name: Haller, George
  last_name: Haller
- first_name: Markus
  full_name: Holzner, Markus
  last_name: Holzner
citation:
  ama: Neamtu-Halic MM, Brizzolara S, Haller G, Holzner M. Unsupervised extraction
    of rotational Lagrangian coherent structures. <i>Computers &#38; Fluids</i>. 2025;290.
    doi:<a href="https://doi.org/10.1016/j.compfluid.2025.106558">10.1016/j.compfluid.2025.106558</a>
  apa: Neamtu-Halic, M. M., Brizzolara, S., Haller, G., &#38; Holzner, M. (2025).
    Unsupervised extraction of rotational Lagrangian coherent structures. <i>Computers
    &#38; Fluids</i>. Elsevier. <a href="https://doi.org/10.1016/j.compfluid.2025.106558">https://doi.org/10.1016/j.compfluid.2025.106558</a>
  chicago: Neamtu-Halic, Marius M., Stefano Brizzolara, George Haller, and Markus
    Holzner. “Unsupervised Extraction of Rotational Lagrangian Coherent Structures.”
    <i>Computers &#38; Fluids</i>. Elsevier, 2025. <a href="https://doi.org/10.1016/j.compfluid.2025.106558">https://doi.org/10.1016/j.compfluid.2025.106558</a>.
  ieee: M. M. Neamtu-Halic, S. Brizzolara, G. Haller, and M. Holzner, “Unsupervised
    extraction of rotational Lagrangian coherent structures,” <i>Computers &#38; Fluids</i>,
    vol. 290. Elsevier, 2025.
  ista: Neamtu-Halic MM, Brizzolara S, Haller G, Holzner M. 2025. Unsupervised extraction
    of rotational Lagrangian coherent structures. Computers &#38; Fluids. 290, 106558.
  mla: Neamtu-Halic, Marius M., et al. “Unsupervised Extraction of Rotational Lagrangian
    Coherent Structures.” <i>Computers &#38; Fluids</i>, vol. 290, 106558, Elsevier,
    2025, doi:<a href="https://doi.org/10.1016/j.compfluid.2025.106558">10.1016/j.compfluid.2025.106558</a>.
  short: M.M. Neamtu-Halic, S. Brizzolara, G. Haller, M. Holzner, Computers &#38;
    Fluids 290 (2025).
date_created: 2025-02-17T09:18:41Z
date_published: 2025-03-01T00:00:00Z
date_updated: 2025-09-30T10:34:32Z
day: '01'
department:
- _id: BjHo
doi: 10.1016/j.compfluid.2025.106558
external_id:
  isi:
  - '001423607400001'
intvolume: '       290'
isi: 1
language:
- iso: eng
month: '03'
oa_version: None
publication: Computers & Fluids
publication_identifier:
  issn:
  - 0045-7930
publication_status: published
publisher: Elsevier
quality_controlled: '1'
related_material:
  link:
  - relation: software
    url: https://github.com/NeamtuMarius/Unsupervised-3D-LAVD-Extraction-Algorithm
scopus_import: '1'
status: public
title: Unsupervised extraction of rotational Lagrangian coherent structures
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 290
year: '2025'
...