Capturing multiscale interactions in fluid flow via Lagrangian coherent structures and modal analysis

Fuente: arXiv
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Autores principales: Jones, Morgan R., Klewicki, Charles, Khan, Oliver, Brunton, Steven L., Luhar, Mitul
Formato: Preprint
Publicado: 2024
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author Jones, Morgan R.
Klewicki, Charles
Khan, Oliver
Brunton, Steven L.
Luhar, Mitul
author_facet Jones, Morgan R.
Klewicki, Charles
Khan, Oliver
Brunton, Steven L.
Luhar, Mitul
contents We consider the relationship between Eulerian modal decompositions and Lagrangian coherent structures (LCSs). The model sensitivity framework developed by Kaszás and Haller (2020) is used to express data-driven modal representations of fluid flow in a Lagrangian space. The method, based on the computation of the finite-time Lyapunov exponent, computes the amplitude perturbations experienced by fluid particles due to specific modal components of the flow. Demonstrations of the method are presented for both periodic and turbulent flows, including experimental data from the wake past an oscillating foil, numerical data of the classical cylinder wake flow, and a direct numerical simulation (DNS) of a turbulent channel flow. This method provides a way to understand how Eulerian mode structures interact dynamically with features of the Lagrangian coherent structure across scales, offering additional physical insight into modal decompositions.
format Preprint
id arxiv_https___arxiv_org_abs_2410_20802
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Capturing multiscale interactions in fluid flow via Lagrangian coherent structures and modal analysis
Jones, Morgan R.
Klewicki, Charles
Khan, Oliver
Brunton, Steven L.
Luhar, Mitul
Fluid Dynamics
We consider the relationship between Eulerian modal decompositions and Lagrangian coherent structures (LCSs). The model sensitivity framework developed by Kaszás and Haller (2020) is used to express data-driven modal representations of fluid flow in a Lagrangian space. The method, based on the computation of the finite-time Lyapunov exponent, computes the amplitude perturbations experienced by fluid particles due to specific modal components of the flow. Demonstrations of the method are presented for both periodic and turbulent flows, including experimental data from the wake past an oscillating foil, numerical data of the classical cylinder wake flow, and a direct numerical simulation (DNS) of a turbulent channel flow. This method provides a way to understand how Eulerian mode structures interact dynamically with features of the Lagrangian coherent structure across scales, offering additional physical insight into modal decompositions.
title Capturing multiscale interactions in fluid flow via Lagrangian coherent structures and modal analysis
topic Fluid Dynamics
url https://arxiv.org/abs/2410.20802