Investigating mode competition and three-dimensional features from two-dimensional velocity fields in an open cavity flow by modal decompositions

Guéniat, Florimond and Pastur, Luc and Lusseyran, Francois (2014) Investigating mode competition and three-dimensional features from two-dimensional velocity fields in an open cavity flow by modal decompositions. Physics of Fluids, 26 (8). ISSN 1070-6631

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Abstract

Shear-layer driven open cavity flows are known to exhibit strong self-sustained oscillations of the shear-layer. Over some range of the control parameters, a competition between two modes of oscillations of the shear layer can occur. We apply both Proper Orthogonal Decomposition and Dynamic Mode Decomposition to experimental two-dimensional two-components time and spaced velocity fields of an incompressible open cavity flow, in a regime of mode competition. We show that, although proper orthogonal decomposition successes in identifying salient features of the flow, it fails at identifying the spatial coherent structures associated with dominant frequencies of the shear-layer oscillations. On the contrary, we show that, as dynamic mode decomposition is devoted to identify spatial coherent structures associated with clearly defined frequency channels, it is well suited for investigating coherentstructuresinintermittentregimes.Weconsiderthevelocitydivergencefield, inordertoidentifyspanwisecoherentfeaturesoftheflow.Finally,weshowthatboth coherent structures in the inner-flow and in the shear-layer exhibit strong spanwise velocitygradients,andarethereforethree-dimensional

Item Type: Article
Additional Information: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Physics of Fluids (1994-present) 26, 085101 (2014); doi: 10.1063/1.4891254 and may be found at https://aip.scitation.org/doi/10.1063/1.4891254.
Subjects: F300 Physics
H100 General Engineering
H900 Others in Engineering
Divisions: Faculty of Computing, Engineering and the Built Environment
Faculty of Computing, Engineering and the Built Environment > School of Engineering and the Built Environment
REF UoA Output Collections > REF 2021 UoA12: Engineering
Depositing User: Euan Scott
Date Deposited: 17 Jan 2019 11:28
Last Modified: 25 Jan 2019 10:42
URI: http://www.open-access.bcu.ac.uk/id/eprint/6860

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