Lois E. Baker
Lagrangian filtering for wave–mean flow decomposition
Baker, Lois E.; Kafiabad, Hossein A.; Maitland-Davies, Cai; Vanneste, Jacques
Authors
Dr Hossein Amini Kafiabad hossein.amini-kafiabad@durham.ac.uk
Associate Professor
Dr Cai Maitland-Davies cai.a.maitland-davies@durham.ac.uk
Post Doctoral Research Associate
Jacques Vanneste
Abstract
Geophysical flows are typically composed of wave and mean motions with a wide range of overlapping temporal scales, making separation between the two types of motion in wave-resolving numerical simulations challenging. Lagrangian filtering – whereby a temporal filter is applied in the frame of the flow – is an effective way to overcome this challenge, allowing clean separation of waves from mean flow based on frequency separation in a Lagrangian frame. Previous implementations of Lagrangian filtering have used particle tracking approaches, which are subject to large memory requirements or difficulties with particle clustering. Kafiabad & Vanneste (2023, Computing Lagrangian means, J. Fluid Mech., vol. 960, A36) recently proposed a novel method for finding Lagrangian means without particle tracking by solving a set of partial differential equations alongside the governing equations of the flow. In this work, we adapt the approach of Kafiabad & Vanneste to develop a flexible, on-the-fly, partial differential equation-based method for Lagrangian filtering using arbitrary convolutional filters. We present several different wave–mean decompositions, demonstrating that our Lagrangian methods are capable of recovering a clean wave field from a nonlinear simulation of geostrophic turbulence interacting with Poincaré waves.
Citation
Baker, L. E., Kafiabad, H. A., Maitland-Davies, C., & Vanneste, J. (2025). Lagrangian filtering for wave–mean flow decomposition. Journal of Fluid Mechanics, 1009, Article A40. https://doi.org/10.1017/jfm.2025.42
Journal Article Type | Article |
---|---|
Acceptance Date | Dec 24, 2024 |
Online Publication Date | Apr 23, 2025 |
Publication Date | Apr 25, 2025 |
Deposit Date | Apr 30, 2025 |
Publicly Available Date | May 14, 2025 |
Journal | Journal of Fluid Mechanics |
Print ISSN | 0022-1120 |
Electronic ISSN | 1469-7645 |
Publisher | Cambridge University Press |
Peer Reviewed | Peer Reviewed |
Volume | 1009 |
Article Number | A40 |
DOI | https://doi.org/10.1017/jfm.2025.42 |
Public URL | https://durham-repository.worktribe.com/output/3806425 |
Files
Published Journal Article
(2 Mb)
PDF
Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/
You might also like
Computing Lagrangian means
(2023)
Journal Article
Inertia-gravity-wave diffusion by geostrophic turbulence: the impact of flow time dependence
(2023)
Journal Article
Inertia-gravity-wave scattering by three-dimensional geostrophic turbulence
(2021)
Journal Article
Wave-averaged balance: a simple example
(2021)
Journal Article
Interaction of Near-Inertial Waves with an Anticyclonic Vortex
(2021)
Journal Article