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Global energy budgets in turbulent Couette and Poiseuille flows

Andreolli, Andrea ORCID iD icon 1; Quadrio, Maurizio; Gatti, Davide 1
1 Institut für Strömungsmechanik (ISTM), Karlsruher Institut für Technologie (KIT)


Turbulent plane Poiseuille and Couette flows share the same geometry, but produce their flow rate owing to different external drivers: pressure gradient and shear, respectively. By looking at integral energy fluxes, we pose and answer the question as to which flow performs better at creating flow rate. We define a flow efficiency, which quantifies the fraction of power used to produce flow rate instead of being wasted as a turbulent overhead; effectiveness, instead, describes the amount of flow rate produced by a given power. The work by Gatti et al. (J. Fluid Mech., vol. 857, 2018, pp. 345–373), where the constant power input concept was developed to compare turbulent Poiseuille flows with drag reduction, is here extended to compare different flows. By decomposing the mean velocity field into a laminar contribution and a deviation, analytical expressions are derived which are the energy-flux equivalents of the FIK identity. These concepts are applied to literature data supplemented by a new set of direct numerical simulations, to find that Couette flows are less efficient but more effective than Poiseuille flows. The reason is traced to the more effective laminar component of Couette flows, which compensates for their higher turbulent activity. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000136616
Veröffentlicht am 24.08.2021
DOI: 10.1017/jfm.2021.598
Zitationen: 3
Web of Science
Zitationen: 3
Zitationen: 8
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Strömungsmechanik (ISTM)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 10.10.2021
Sprache Englisch
Identifikator ISSN: 0022-1120, 1469-7645
KITopen-ID: 1000136616
Erschienen in Journal of fluid mechanics
Verlag Cambridge University Press (CUP)
Band 924
Seiten Article no: A25
Vorab online veröffentlicht am 13.08.2021
Schlagwörter turbulence theory
Nachgewiesen in Dimensions
Web of Science
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