Nonlinear stochastic modelling with Langevin regression
File(s)rspa.2021.0092.pdf (2.04 MB)
Published version
Author(s)
Callaham, JL
Loiseau, J-C
Rigas, G
Brunton, SL
Type
Journal Article
Abstract
Many physical systems characterized by nonlinear multiscale interactions can be modelled by treating unresolved degrees of freedom as random fluctuations. However, even when the microscopic governing equations and qualitative macroscopic behaviour are known, it is often difficult to derive a stochastic model that is consistent with observations. This is especially true for systems such as turbulence where the perturbations do not behave like Gaussian white noise, introducing non-Markovian behaviour to the dynamics. We address these challenges with a framework for identifying interpretable stochastic nonlinear dynamics from experimental data, using forward and adjoint Fokker–Planck equations to enforce statistical consistency. If the form of the Langevin equation is unknown, a simple sparsifying procedure can provide an appropriate functional form. We demonstrate that this method can learn stochastic models in two artificial examples: recovering a nonlinear Langevin equation forced by coloured noise and approximating the second-order dynamics of a particle in a double-well potential with the corresponding first-order bifurcation normal form. Finally, we apply Langevin regression to experimental measurements of a turbulent bluff body wake and show that the statistical behaviour of the centre of pressure can be described by the dynamics of the corresponding laminar flow driven by nonlinear state-dependent noise.
Date Issued
2021-06-30
Date Acceptance
2021-05-04
Citation
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2021, 477 (2250), pp.1-28
ISSN
1364-5021
Publisher
The Royal Society
Start Page
1
End Page
28
Journal / Book Title
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume
477
Issue
2250
Copyright Statement
© 2021 The Authors. Published by the Royal Society under the terms of theCreative Commons Attribution Licensehttp://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author andsource are credited.
License URL
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000660775900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
system identification
data-driven modelling
stochastic modelling
Langevin equation
Fokker-Planck equation
sparse regression
SPECTRAL PROPERTIES
IDENTIFICATION
REDUCTION
DYNAMICS
PATTERN
APPROXIMATION
PARAMETERS
CYLINDER
SYSTEMS
FLOWS
Publication Status
Published
Article Number
ARTN 20210092
Date Publish Online
2021-06-02