Short Time Proper Orthogonal Decomposition for State Estimation of Transient Flow Fields

Siegel, Stefan; Cohen, Kelly; Seidel, Jürgen; McLaughlin, Thomas

doi:10.2514/6.2005-296

Cited by 18 publications

(17 citation statements)

References 9 publications

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“…Although this decomposition is well suited to time periodic flow fields, it faces problems for transient flows [21]. Different additions to the basic POD procedure have been proposed; the most notable is the addition of a shift mode as introduced independently by Noack et al [12] as well as Siegel et al [10].…”

Section: Development Of a Low-dimensional Model Based On Podmentioning

confidence: 98%

“…Therefore, snapshot selection procedures and extensions to POD that addresses the changes in the flow field need to be developed. In terms of snapshot selection, Siegel et al [11] showed that a small integer number of shedding cycles (as small as a single cycle) are sufficient to accurately represent the flow state during this cycle with relatively few POD modes. Regarding extensions to POD for non-periodic flows, Noack et al [12] and Siegel et al [10] independently developed models containing a 'shift mode' or 'mean flow mode', which accounts for the change in the mean flow due to successful flow control.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Feedback control of a circular cylinder wake

Seidel

Siegel

Fagley

et al. 2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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Feedback flow control of a three-dimensional wake behind a circular cylinder at a Reynolds number of Re = 100 was investigated. A combination of numerical simulations, experiments, and control theory was used to understand the flow field and to develop a sensor configuration, a flow state estimator, and a controller. The flow field was analysed by using proper orthogonal decomposition (POD) in two dimensions, and two-dimensional and threedimensional sensor placements were investigated. The controller input was computed from the POD time coefficients, and actuation was performed by using rigid cylinder motion normal to the free stream. In the two-dimensional computations, feedback was shown to effectively reduce the drag and the fluctuating lift force. When feedback forcing was applied in the threedimensional wake, both simulations and experiments showed that the vortex shedding could be controlled initially and the amplitude of the fluctuations decreased. However, spanwise phase variations eventually appeared and rendered the controller ineffective.

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Section: Development Of a Low-dimensional Model Based On Podmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Feedback control of a circular cylinder wake

Seidel

Siegel

Fagley

et al. 2008

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Gillies (1995) and Siegel et al (2005) have shown that for time periodic flows, modes identical to those obtained from snapshot ensembles containing a large number of shedding cycles can be obtained using snapshot ensembles of small integer number of cycles, down to a minimum of one shedding cycle. Snapshot ensembles that are non-integer multiples of shedding cycles lead to distorted POD modes.…”

Section: Short Time Pod -Spodmentioning

confidence: 98%

Reduced-Order Modelling for Flow Control

Noack¹,

Morzyński²,

Tadmor³

2011

CISM International Centre for Mechanical Sciences

193

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“…Secondly, it appears that the feedback controlled flow does not leave the subspace spanned by open loop and unforced startup data, which may have important implications for the performance limits of feedback flow control. Further details on this approach are presented by Siegel et al (2005a) and Seidel et al (2006).…”

Section: B Open-loop Transient Excitation Using Actuatorsmentioning

confidence: 99%