Reduced order state-space models from the pulse responses of a linearized CFD scheme

Ann L. Gaitonde, D. P. Jones*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

32 Citations (Scopus)

Abstract

This paper describes a method for obtaining a time continuous reduced order model (ROM) from a system of time continuous linear differential equations. These equations are first put into a time discrete form using a finite difference approximation. The unit sample responses of the discrete system are calculated for each system input and these provide the Markov parameters of the system. An eigenvalue realization algorithm (ERA) is used to construct a discrete ROM. This ROM is then used to obtain a continuous ROM of the original continuous system. The focus of this paper is on the application of this method to the calculation of unsteady flows using the linearized Euler equations on moving meshes for aerofoils undergoing heave or linearized pitch motions. Applying a standard cell-centre spatial discretization and taking account of mesh movement a continuous system of differential equations is obtained which are continuous in time. These are put into discrete time form using an implicit finite difference approximation. Results are presented demonstrating the efficiency of the system reduction method for this system.
Translated title of the contributionReduced order state-space models from the pulse responses of a linearized CFD scheme
Original languageEnglish
Pages (from-to)581-606
Number of pages26
JournalInternational Journal for Numerical Methods in Fluids
Volume42
Issue number6
DOIs
Publication statusPublished - 30 Jun 2003

Bibliographical note

Publisher: Wiley

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