Effective adjoint approaches for computational fluid dynamics

GKW Kenway, CA Mader, P He… - Progress in Aerospace …, 2019 - Elsevier
The adjoint method is used for high-fidelity aerodynamic shape optimization and is an
efficient approach for computing the derivatives of a function of interest with respect to a …

Divide and conquer: Learning chaotic dynamical systems with multistep penalty neural ordinary differential equations

D Chakraborty, SW Chung, T Arcomano… - Computer Methods in …, 2024 - Elsevier
Forecasting high-dimensional dynamical systems is a fundamental challenge in various
fields, such as geosciences and engineering. Neural Ordinary Differential Equations …

Sensitivity analysis on chaotic dynamical systems by Non-Intrusive Least Squares Shadowing (NILSS)

A Ni, Q Wang - Journal of Computational Physics, 2017 - Elsevier
This paper develops the Non-Intrusive Least Squares Shadowing (NILSS) method, which
computes the sensitivity for long-time averaged objectives in chaotic dynamical systems. In …

Dyslim: Dynamics stable learning by invariant measure for chaotic systems

Y Schiff, ZY Wan, JB Parker, S Hoyer… - arxiv preprint arxiv …, 2024 - arxiv.org
Learning dynamics from dissipative chaotic systems is notoriously difficult due to their
inherent instability, as formalized by their positive Lyapunov exponents, which exponentially …

[HTML][HTML] Error-driven adaptive mesh refinement for unsteady turbulent flows in spectral-element simulations

N Offermans, D Massaro, A Peplinski, P Schlatter - Computers & Fluids, 2023 - Elsevier
The simulation of turbulent flows requires high spatial resolution in potentially a priori
unknown, solution-dependent locations. To achieve adaptive refinement of the mesh, we …

Adjoint sensitivity analysis of chaotic dynamical systems with non-intrusive least squares shadowing

PJ Blonigan - Journal of Computational Physics, 2017 - Elsevier
This paper presents a discrete adjoint version of the recently developed non-intrusive least
squares shadowing (NILSS) algorithm, which circumvents the instability that conventional …

Gradient-free aerodynamic shape optimization using large eddy simulation

HR Karbasian, BC Vermeire - Computers & Fluids, 2022 - Elsevier
In this paper we demonstrate the ability to perform gradient-free aerodynamic shape
optimization using Large Eddy Simulation (LES) with the Mesh Adaptive Direct Search …

Hyperbolicity, shadowing directions and sensitivity analysis of a turbulent three-dimensional flow

A Ni - Journal of Fluid Mechanics, 2019 - cambridge.org
This paper uses compressible flow simulation to analyse the hyperbolicity, shadowing
directions and sensitivities of a weakly turbulent three-dimensional cylinder flow at Reynolds …

Multiple shooting shadowing for sensitivity analysis of chaotic dynamical systems

PJ Blonigan, Q Wang - Journal of Computational Physics, 2018 - Elsevier
Sensitivity analysis methods are important tools for research and design with simulations.
Many important simulations exhibit chaotic dynamics, including scale-resolving turbulent …

[HTML][HTML] Improving transonic performance with adjoint-based NACA 0012 airfoil design optimization

EL Ntantis, V Xezonakis - Results in Engineering, 2024 - Elsevier
This study delves into the discrete adjoint method, a powerful tool in high-fidelity
aerodynamic shape optimization that efficiently computes derivatives of a target function for …