Modal decomposition of flow fields and convective heat transfer maps: An application to wall-proximity square ribs

Raiola, Marco; Mallor, Fermı́n; Discetti, Stefano; Ianiro, Andrea

doi:10.1016/j.expthermflusci.2018.12.023

Cited by 12 publications

(15 citation statements)

References 49 publications

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“…With respect to a future experimental set-up to test the capabilities of CNNs to reconstruct LSMs, recent investigations have shown that it is possible to obtain time-resolved heattransfer maps with resolutions of the order of 100 × 100 [66][67][68] . Whereas the relationship between heat-transfer maps and wall-shear-stress measurements have been shown in Ref.…”

Section: Discussionmentioning

confidence: 99%

Sensing the turbulent large-scale motions with their wall signature

2019

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This study assesses the capability of extended proper orthogonal decomposition (EPOD) and convolutional neural networks (CNNs) to reconstruct large-scale and very-large-scale motions (LSMs and VLSMs respectively) employing wall-shear-stress measurements in wall-bounded turbulent flows. Both techniques are used to reconstruct the instantaneous LSMs evolution in the flow field as a combination of proper orthogonal decomposition (POD) modes, employing a limited set of instantaneous wall-shear-stress measurements. Due to the dominance of non-linear effects, only CNNs provide satisfying results. Being able to account for nonlinearities in the flow, CNNs are shown to perform significantly better than EPOD both in terms of instantaneous flow field estimation and turbulent statistics reconstruction. CNNs are able to provide a more effective reconstruction performance employing more POD modes, at larger distances from the wall and employing lower wall-measurement resolutions. Furthermore, the capability of tackling non-linear features of CNNs results in estimation capabilities that are weakly dependent on the distance from the wall.

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Section: Discussionmentioning

confidence: 99%

Sensing the turbulent large-scale motions with their wall signature

2019

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“…[1,2]). The appeal and the simplicity of such passive devices triggered a wide scientific interest [3,4,5,6,7] which continues unabated [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…A similar effect has been observed by Hearst et al [11] for wall-mounted cubes in ZPG TBLs. The flow downstream of the rib is mainly dominated by eddies shed by the rib [8,9] which superpose on the large-scale motions dominating the outer region of TBLs. The effect of these vortical structures on the heat-transfer efficiency was recently studied by Mallor et al [9].…”

Section: Introductionmentioning

confidence: 99%

“…The flow downstream of the rib is mainly dominated by eddies shed by the rib [8,9] which superpose on the large-scale motions dominating the outer region of TBLs. The effect of these vortical structures on the heat-transfer efficiency was recently studied by Mallor et al [9]. In their study, flow-field and heat-transfer measurements downstream of wall-proximity ribs were combined to explore the correlation between instantaneous flow-field and wall convective heattransfer features.…”

Section: Introductionmentioning

confidence: 99%

“…[19] also reports the modal analysis for the same database, showing a reduction of energy in the first modes due to the destruction of large-scale motions when compared with canonical turbulent channel flows without ribs; this result is in agreement with the recent findings reported in Refs. [8,9]. Shah and Tachie [17] report that the APG affects the flow statistics across a larger portion of the channel when compared with the flow under favourable pressure gradient (FPG).…”

Section: Introductionmentioning

confidence: 99%

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