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Complex nonlinear turbulent dynamical systems are ubiquitous in many areas. Recovering unobserved state variables is an important topic for the data assimilation of turbulent systems. In this article, an efficient continuous in time data…

Fluid Dynamics · Physics 2021-11-03 Nan Chen , Yuchen Li , Evelyn Lunasin

A thermal convection loop is a annular chamber filled with water, heated on the bottom half and cooled on the top half. With sufficiently large forcing of heat, the direction of fluid flow in the loop oscillates chaotically, dynamics…

Dynamical Systems · Mathematics 2016-06-24 Andrew J. Reagan , Yves Dubief , Peter Sheridan Dodds , Christopher M. Danforth

We develop a versatile optimization method, which finds the design parameters that minimize time-averaged acoustic cost functionals. The method is gradient-free, model-informed, and data-driven with reservoir computing based on echo state…

Fluid Dynamics · Physics 2022-02-03 Francisco Huhn , Luca Magri

This paper contains the latest installment of the authors' project on developing ensemble based data assimilation methodology for high dimensional fluid dynamics models. The algorithm presented here is a particle filter that combines model…

Numerical Analysis · Mathematics 2020-04-22 Colin Cotter , Dan Crisan , Darryl Holm , Wei Pan , Igor Shevchenko

Data assimilation algorithms are used to estimate the states of a dynamical system using partial and noisy observations. The ensemble Kalman filter has become a popular data assimilation scheme due to its simplicity and robustness for a…

Numerical Analysis · Mathematics 2021-06-23 Gottfried Hastermann , Maria Reinhardt , Rupert Klein , Sebastian Reich

Data assimilation (DA) is a fundamental computational technique that integrates numerical simulation models and observation data on the basis of Bayesian statistics. Originally developed for meteorology, especially weather forecasting, DA…

Data assimilation, consisting in the combination of a dynamical model with a set of noisy and incomplete observations in order to infer the state of a system over time, involves uncertainty in most settings. Building upon an existing…

Machine Learning · Computer Science 2026-03-02 Anthony Frion , David S Greenberg

Starting from limited measurements of a turbulent flow, data assimilation (DA) attempts to estimate all the spatio-temporal scales of motion. Success is dependent on whether the system is observable from the measurements, or how much of the…

Fluid Dynamics · Physics 2026-02-16 Andrew Cleary , Qi Wang , Tamer A. Zaki

The use of data assimilation technique to identify optimal topography is discussed in frames of time-dependent motion governed by non-linear barotropic ocean model. Assimilation of artificially generated data allows to measure the influence…

Atmospheric and Oceanic Physics · Physics 2009-12-08 Eugene Kazantsev

Data assimilation refers to the problem of finding trajectories of a prescribed dynamical model in such a way that the output of the model (usually some function of the model states) follows a given time series of observations. Typically…

Atmospheric and Oceanic Physics · Physics 2015-05-30 Jochen Bröcker , Ivan G. Szendro

A goal of data assimilation is to infer stochastic dynamical behaviors with available observations. We consider transition phenomena between metastable states for a stochastic system with (non-Gaussian) $\alpha-$stable L\'evy noise. With…

Dynamical Systems · Mathematics 2016-06-29 Ting Gao , Jinqiao Duan , Xingye Kan

Data assimilation is a central problem in many geophysical applications, such as weather forecasting. It aims to estimate the state of a potentially large system, such as the atmosphere, from sparse observations, supplemented by prior…

Machine Learning · Computer Science 2024-06-24 Matthieu Blanke , Ronan Fablet , Marc Lelarge

A framework for deriving probabilistic data-driven closure models is proposed for coarse-grained numerical simulations of turbulence in statistically stationary state. The approach unites the ideal large-eddy simulation model and data…

Fluid Dynamics · Physics 2025-03-25 Sagy Ephrati

Thermoacoustic instabilities in gas turbines and aeroengine combustors falls within the category of complex systems. They can be described phenomenologically using nonlinear stochastic differential equations, which constitute the grounds…

Fluid Dynamics · Physics 2016-12-09 Edouard Boujo , Alexey Denisov , Bruno Schuermans , Nicolas Noiray

There is an urgent need to build models to tackle Indoor Air Quality issue. Since the model should be accurate and fast, Reduced Order Modelling technique is used to reduce the dimensionality of the problem. The accuracy of the model, that…

Data assimilation (DA) aims at optimally merging observational data and model outputs to create a coherent statistical and dynamical picture of the system under investigation. Indeed, DA aims at minimizing the effect of observational and…

Data Analysis, Statistics and Probability · Physics 2022-01-05 Yumeng Chen , Alberto Carrassi , Valerio Lucarini

Data assimilation has become a key technique for combining physical models with observational data to estimate state variables. However, classical assimilation algorithms often struggle with the high nonlinearity present in both physical…

Machine Learning · Computer Science 2025-07-22 Zhuoyuan Li , Bin Dong , Pingwen Zhang

The analysis of high-dimensional dynamical systems generally requires the integration of simulation data with experimental measurements. Experimental data often has substantial amounts of measurement noise that compromises the ability to…

Numerical Analysis · Mathematics 2019-10-02 Samuel Rudy , Steven Brunton , J. Nathan Kutz

Variational data assimilation optimizes for an initial state of a dynamical system such that its evolution fits observational data. The physical model can subsequently be evolved into the future to make predictions. This principle is a…

Machine Learning · Computer Science 2021-05-21 Thomas Frerix , Dmitrii Kochkov , Jamie A. Smith , Daniel Cremers , Michael P. Brenner , Stephan Hoyer

Data assimilation techniques, such as ensemble Kalman filtering, have been shown to be a highly effective and efficient way to combine noisy data with a mathematical model to track and forecast dynamical systems. However, when dealing with…

Dynamical Systems · Mathematics 2023-05-17 Stephen A Falconer , David J. B. Lloyd , Naratip Santitissadeekorn