Coherent structures and chaos: A model problem

Sirovich, Lawrence; Rodríguez, J. D.

doi:10.1016/0375-9601(87)90209-x

Cited by 133 publications

(53 citation statements)

References 7 publications

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“…The procedure developed here does give an upper bound on the dimension of the attractor through the actual construction of an embedding space. In the one instance in which the method has been carried to completion [20] the dimension of our description falls within the theoretical estimate given by Whitney [21],…”

supporting

confidence: 70%

“…While these three papers do not present concrete numerical examples of the methodology, some evidence supporting its usefulness is available. The results of two investigations using this approach have been published [20,24], The former treats the Ginzburg-Landau equation and the second a problem in pattern recognition. In both instances the degree of success was encouraging.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Turbulence and the dynamics of coherent structures. I. Coherent structures

Sirovich¹

1987

Quart. Appl. Math.

5,103

2,730

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supporting

confidence: 70%

mentioning

confidence: 99%

Turbulence and the dynamics of coherent structures. I. Coherent structures

Sirovich¹

1987

Quart. Appl. Math.

5,103

2,730

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“…The method used in the present study is Sirovich's Snapshot POD Method [7]. Figure 10 shows accumulated plots of instantaneous velocity fluctuation profile at X/C=0.95, and instantaneous velocity fluctuation component reconstructed from the dominant POD modes for both Case A and Case B.…”

Section: Resultsmentioning

confidence: 99%

“…Based on the computed results investigations are presented on the effects of the free-stream turbulence on the boundary layer transition, and behavior of the pressure waves that originate near the trailing-edge with its effects on the separation/transition of the boundary layer [6]. Also presented in this paper are the dominant unsteady behaviors in the transitional boundary layers that are extracted by Snapshot Proper Orthogonal Decomposition (POD) Analysis [7].…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of compressible transitional cascade flows

Matsuura¹,

Kato

2006

WIT Transactions on Engineering Sciences, Vol 52

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The large eddy simulation (LES) of compressible transitional flows in a low-pressure turbine cascade is performed by using 6 th -order compact difference and 10 th -order filtering method. The numerical results without free-stream turbulence and those with about 5% of free-stream turbulence are compared. In these simulations, separated-flows in the turbine cascade accompanied by laminar-turbulent transition are realized, and the present results closely agree with past experimental measurements in terms of the static pressure distribution around the blade. In the case where no free-stream turbulence is taken into account, unsteady pressure field essentially differs from that with strong free-stream turbulence. In the no free-stream turbulence case, pressure waves that propagate from blade's wake region have noticeable effects on the separated-boundary layer near the trailing-edge, and on the neighboring blade. Also, based on Snapshot Proper Orthogonal Decomposition (POD) analysis, dominant behaviors of the transitional boundary layers are investigated.

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“…A quantitative assessment of unsteadiness was made via snapshot Proper Orthogonal Decomposition (POD) 77,79,80 of WSS fluctuations σ f (x, t) = σ(x, t) −σ(x) for the Newtonian simulation, where σ(x, t) is the WSS field, andσ(x) is the time-averaged WSS field. Specifically, snapshot POD of σ f (x, t) was undertaken in T 1 using 1000 temporal snapshots with a uniform spacing of 0.001 s. Figure 12 shows the Power Spectral Density (PSD) of a 1 (t) and a 5 (t), the first and fifth temporal POD modes, respectively, for the Newtonian simulation.…”

Section: Snapshot Proper Orthogonal Decompositionmentioning

confidence: 99%

Suppressing unsteady flow in arterio-venous fistulae

et al. 2017

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Arterio-Venous Fistulae (AVF) are regarded as the “gold standard” method of vascular access for patients with end-stage renal disease who require haemodialysis. However, a large proportion of AVF do not mature, and hence fail, as a result of various pathologies such as Intimal Hyperplasia (IH). Unphysiological flow patterns, including high-frequency flow unsteadiness, associated with the unnatural and often complex geometries of AVF are believed to be implicated in the development of IH. In the present study, we employ a Mesh Adaptive Direct Search optimisation framework, computational fluid dynamics simulations, and a new cost function to design a novel non-planar AVF configuration that can suppress high-frequency unsteady flow. A prototype device for holding an AVF in the optimal configuration is then fabricated, and proof-of-concept is demonstrated in a porcine model. Results constitute the first use of numerical optimisation to design a device for suppressing potentially pathological high-frequency flow unsteadiness in AVF.

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Coherent structures and chaos: A model problem

Cited by 133 publications

References 7 publications

Turbulence and the dynamics of coherent structures. I. Coherent structures

Turbulence and the dynamics of coherent structures. I. Coherent structures

Large eddy simulation of compressible transitional cascade flows

Suppressing unsteady flow in arterio-venous fistulae

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