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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Resolvent-based estimation of turbulent channel flow using wall measurements

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Author(s):
Amaral, Filipe R. [1] ; Cavalieri, Andre V. G. [1] ; Martini, Eduardo [2] ; Jordan, Peter [2] ; Towne, Aaron [3]
Total Authors: 5
Affiliation:
[1] Inst Tecnol Aeronaut, Div Engn Aeronaut, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[2] Univ Poitiers, CNRS, ENSMA, Dept Fluides Therm Combust, Inst Pprime, F-86000 Poitiers - France
[3] Univ Michigan, Dept Mech Engn, Ann Arbor, MI 48109 - USA
Total Affiliations: 3
Document type: Journal article
Source: JOURNAL OF FLUID MECHANICS; v. 927, SEP 24 2021.
Web of Science Citations: 1
Abstract

We employ a resolvent-based methodology to estimate velocity and pressure fluctuations within turbulent channel flows at friction Reynolds numbers of approximately 180, 550 and 1000 using measurements of shear stress and pressure at the walls, taken from direct numerical simulation (DNS) databases. Martini et al. (J. Fluid Mech., vol. 900, 2021, p. A2) showed that the resolvent-based estimator is optimal when the true space-time forcing statistics are utilised, thus providing an upper bound for the accuracy of any linear estimator. We use this framework to determine the flow structures that can be linearly estimated from wall measurements, and we characterise these structures and the estimation errors in both physical and wavenumber space. We also compare these results to those obtained using approximate forcing models - an eddy-viscosity model and white-noise forcing - and demonstrate the significant benefit of using true forcing statistics. All models lead to accurate results up to the buffer layer, but only using the true forcing statistics allows accurate estimation of large-scale logarithmic-layer structures, with significant correlation between the estimates and DNS results throughout the channel. The eddy-viscosity model displays an intermediate behaviour, which may be related to its ability to partially capture the forcing colour. Our results show that structures that leave a footprint on the channel walls can be accurately estimated using the linear resolvent-based methodology, and the presence of large-scale wall-attached structures enables accurate estimations through the logarithmic layer. (AU)

FAPESP's process: 19/02203-2 - Study of inverse problems on turbulence and aeroacoustics employing the resolvent analysis
Grantee:Filipe Ramos do Amaral
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 19/27655-3 - Control-oriented reduced-order modelling for aerodynamics and aeroacoustics
Grantee:André Valdetaro Gomes Cavalieri
Support Opportunities: Regular Research Grants