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An EnKF-Based Flow State Estimator for Aerodynamic Flows

da Silva, Andre F. C. and Colonius, Tim (2017) An EnKF-Based Flow State Estimator for Aerodynamic Flows. In: 8th AIAA Theoretical Fluid Mechanics Conference, 5-9 June 2017, Denver, CO. https://resolver.caltech.edu/CaltechAUTHORS:20190709-092100532

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Abstract

Regardless of plant model, robust flow estimation based on limited measurements remains a major obstacle to successful flow control applications. Aiming to combine the robustness of a high-dimensional representation of the dynamics with the cost efficiency of a low-order approximation of the state covariance matrix, a flow state estimator based on the Ensemble Kalman Filter (EnKF) is applied to two-dimensional flow past a cylinder and an airfoil at high angle of attack and low Reynolds number. For the development purposes, we use the numerical algorithm as both the estimator and as a surrogate for the measurements. Estimation is successful using a reduced number of either pressure sensors on the surface of the body or sparsely placed velocity probes in the wake. Because the most relevant features of these flows is restricted to a low-dimensional subspace/manifold of the state space, asymptotic behavior of the estimator is shown to be achieved with a small ensemble size. The relative importance of each sensor location is evaluated by analyzing how they influence the estimated flow field. Covariance inflation is used to enhance the estimator performance in the presence of unmodeled free stream perturbations. A combination of parametric modeling and augmented state methodology is used to successfully estimate the forces on immersed bodies.


Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/6.2017-3483DOIConference Paper
https://arc.aiaa.org/doi/10.2514/6.2017-3483PublisherConference Paper
ORCID:
AuthorORCID
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2017 American Institute of Aeronautics and Astronautics. Published Online: 2 Jun 2017. This work has been supported in part by a grant from AFOSR (FA9550-14-1-0328) with Dr. Douglas Smith as program manager. A.F.C. da Silva would like to thank the Ministry of Education of Brazil (Capes Foundation) for its support through a Science without Borders scholarship (Grant number BEX 12966/13-4). The authors also acknowledge Prof. Andrew Stuart, Prof. David Williams and Prof. Jeff Eldredge for helpful discussions of this work.
Funders:
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-14-1-0328
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)BEX 12966/13-4
Subject Keywords:Theoretical Fluid Mechanics
Other Numbering System:
Other Numbering System NameOther Numbering System ID
AIAA2017-3483
Record Number:CaltechAUTHORS:20190709-092100532
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190709-092100532
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96968
Collection:CaltechAUTHORS
Deposited By: Melissa Ray
Deposited On:11 Jul 2019 16:51
Last Modified:03 Oct 2019 21:27

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