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Coherent large scale structures in adverse pressure gradient turbulent boundary layers

Hain, Rainer and Scharnowski, Sven and Reuther, Nico and Kähler, C. J. and Schröder, Andreas and Geisler, Reinhard and Agocs, Janos and Röse, Anni and Novara, Matteo and Stanislas, M. and Cuvier, C. and Foucaut, J. M. and Srinath, S. and Laval, J. P. and Willert, Christian and Klinner, Joachim and Soria, Julio and Amili, O. and Atkinson, C. (2016) Coherent large scale structures in adverse pressure gradient turbulent boundary layers. 18th Int. Symposium on Application of Laser Techniques to Fluid Mechanics- PIV16, 04.-07. Juli 2016, Lisbon, Portugal.

Full text not available from this repository.

Official URL: http://ltces.dem.ist.utl.pt/lxlaser/lxlaser2016/

Abstract

Over the last several years, the observation of large scale turbulent flow structures in turbulent boundary layer flows has stimulated intense experimental and numerical investigations with the aim of characterizing not only the topological features of the coherent structures but also their dynamics. Due to the large length of the structures (approximately 7-14 times the boundary layer thickness) it is very difficult to analyze them reliably since both a large field of view and a high spatial resolution are simultaneously required to measure all relevant spatial scales. Moreover, a low uncertainty of the experimental techniques is required as the disturbance of the mean velocity field due to the large scale structures can be quite weak. This holds in particular true for investigations at small Reynolds numbers. As a consequence of the recent technological progress, the required measurement uncertainty can be reached with sophisticated image analysis techniques but the resolution of the structures requires a high number of cameras. Therefore, 16 sCMOS cameras in total were provided by different research organizations in order to perform large scale turbulent boundary layer measurements with appropriate spatial resolution. In the case of adverse pressure gradients (APG) the topology and dynamics of the large scale turbulent flow structures is unknown, as is their significance for the statistical properties of the flow. Therefore the fundamental aim of this project was to resolve and characterize these structures in an APG boundary layer flow at the Laboratoire de Mécanique de Lille (LML) wind tunnel. To access the span-wise / wall normal signature of the structures as well, stereoscopic PIV measurements in span-wise/wall-normal planes were performed at specific stream-wise locations in addition. To complement these large field of view measurements, long-range micro-PIV, time resolved near wall velocity profiles and film-based measurements were performed in order to determine the wall-shear stress and ist fluctuations at some specific locations along the model, see Soria et al. (2016).

Item URL in elib:https://elib.dlr.de/103443/
Document Type:Conference or Workshop Item (Speech)
Title:Coherent large scale structures in adverse pressure gradient turbulent boundary layers
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Hain, RainerUni BW München, Inst f Strömungsmechanik und AerodynamikUNSPECIFIED
Scharnowski, SvenUni BW München, Inst f Strömungsmechanik und AerodynamikUNSPECIFIED
Reuther, NicoNico.Reuther (at) unibw.deUNSPECIFIED
Kähler, C. J.Uni BW München, Inst f Strömungsmechanik und AerodynamikUNSPECIFIED
Schröder, Andreasandreas.schroeder (at) dlr.deUNSPECIFIED
Geisler, Reinhardreinhard.geisler (at) dlr.deUNSPECIFIED
Agocs, Janosjanos.agocs (at) dlr.deUNSPECIFIED
Röse, AnniAS-EXVUNSPECIFIED
Novara, Matteomatteo.novara (at) dlr.deUNSPECIFIED
Stanislas, M.LML UMR CNRS 8107, Villeneuve d'Ascq, FranceUNSPECIFIED
Cuvier, C.LML UMR CNRS 8107, Villeneuve d'Ascq, FranceUNSPECIFIED
Foucaut, J. M.LML UMR CNRS 8107, Villeneuve d'Ascq, FranceUNSPECIFIED
Srinath, S.LML UMR CNRS 8107, Villeneuve d'Ascq, FranceUNSPECIFIED
Laval, J. P.LML UMR CNRS 8107, Villeneuve d'Ascq, FranceUNSPECIFIED
Willert, Christianchris.willert (at) dlr.deUNSPECIFIED
Klinner, Joachimjoachim.klinner (at) dlr.deUNSPECIFIED
Soria, JulioMonash UniversityUNSPECIFIED
Amili, O.Monash UniversityUNSPECIFIED
Atkinson, C.Monash UniversityUNSPECIFIED
Date:2016
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:PIV, turbulent boundary layer, adverse pressure gradient, large scale structures
Event Title:18th Int. Symposium on Application of Laser Techniques to Fluid Mechanics- PIV16
Event Location:Lisbon, Portugal
Event Type:international Conference
Event Dates:04.-07. Juli 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation and Validation
Location: Göttingen , Köln-Porz
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Institute of Propulsion Technology > Engine Measurement Systems
Deposited By: Bachmann, Barbara
Deposited On:16 Sep 2016 13:48
Last Modified:14 Oct 2016 10:12

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