A stabilized march approach to adjoint-based sensitivity analysis of chaotic flows

Fuente: arXiv
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Main Authors: Thakur, Pranshul, Nadarajah, Siva
Format: Preprint
Published: 2025
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author Thakur, Pranshul
Nadarajah, Siva
author_facet Thakur, Pranshul
Nadarajah, Siva
contents Adjoint-based sensitivity analysis is of interest in computational science due to its ability to compute sensitivities at a lower cost with respect to several design parameters. However, conventional sensitivity analysis methods fail in the presence of chaotic flows. Popular approaches to chaotic sensitivity analysis of flows involve the use of the shadowing trajectory. The state-of-the-art approach computes the shadowing trajectory by solving a least squares minimization problem, resulting in a space-time linear system of equations. The current paper computes the adjoint shadowing trajectory using the stabilized march, by specifying the adjoint boundary conditions instead of solving a minimization problem. This approach results in a space-time linear system that can be solved through a single backward substitution of order $\mathcal{O}(n_u^2)$ with $n_u$ being the dimension of the unstable subspace. It is proven to compute sensitivities that converge to the true sensitivity for large integration times and that the error in the sensitivity due to the discretization is of the order of the local truncation error of the scheme. The approach is numerically verified on the Lorentz 63 and Kuramoto-Sivasinsky equations.
format Preprint
id arxiv_https___arxiv_org_abs_2505_00838
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A stabilized march approach to adjoint-based sensitivity analysis of chaotic flows
Thakur, Pranshul
Nadarajah, Siva
Numerical Analysis
Optimization and Control
34A34, 37A99, 37D20, 37D45, 37N30, 46N40, 65P99, 76F20
Adjoint-based sensitivity analysis is of interest in computational science due to its ability to compute sensitivities at a lower cost with respect to several design parameters. However, conventional sensitivity analysis methods fail in the presence of chaotic flows. Popular approaches to chaotic sensitivity analysis of flows involve the use of the shadowing trajectory. The state-of-the-art approach computes the shadowing trajectory by solving a least squares minimization problem, resulting in a space-time linear system of equations. The current paper computes the adjoint shadowing trajectory using the stabilized march, by specifying the adjoint boundary conditions instead of solving a minimization problem. This approach results in a space-time linear system that can be solved through a single backward substitution of order $\mathcal{O}(n_u^2)$ with $n_u$ being the dimension of the unstable subspace. It is proven to compute sensitivities that converge to the true sensitivity for large integration times and that the error in the sensitivity due to the discretization is of the order of the local truncation error of the scheme. The approach is numerically verified on the Lorentz 63 and Kuramoto-Sivasinsky equations.
title A stabilized march approach to adjoint-based sensitivity analysis of chaotic flows
topic Numerical Analysis
Optimization and Control
34A34, 37A99, 37D20, 37D45, 37N30, 46N40, 65P99, 76F20
url https://arxiv.org/abs/2505.00838