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Global and local skin friction diagnostics from TSP surface patterns on anunderwater cylinder in crossflow

Miozzi, Massimo and Capone, Alessandro and Di Felice, Fabio and Klein, Christian and Liu, Tianshu (2016) Global and local skin friction diagnostics from TSP surface patterns on anunderwater cylinder in crossflow. Physics of Fluids, 28 (28). American Institute of Physics (AIP). DOI: 10.1063/1.4968525 ISSN 1070-6631

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Official URL: http://scitation.aip.org/content/aip/journal/pof2/28/12?ver=pdfcov


A systematical method is formulated for extracting skin-friction fields from Temperature Sensitive Paint (TSP) images in the sense of time-averaging and phase-averaging. The method is applied to an underwater cylinder in crossflow at two subcrit ica l regimes (Re = 72 000 and 144 000). TSP maps are decomposed in a time-averaged, a phase-averaged, and a random component. The asymptotic form of the energy equation at the wall provides an Euler-Lagrange equation set that is solved numerically to gain the relative skin friction time- and phase-averaged fields from the TSP surface temperature maps. The comparison of the time averaged relative skin-friction profiles with the literature data shows an excellent agreement on the whole laminar boundary layer up to t he laminar separation line. Downstream of separation, t ime averaged results identify the secondary reattachment/separation events, which are lost in the available literature data. The periodic behavior of the skin-friction is taken, describing how the laminar separation bubble evolves by providing the time history of the laminar separation line and of the secondary reattachment/separation over the entire vortex shedding period. lnstantaneous skin friction maps reveal the existence of coherent structures by capturing their footprint on the cylinder' s surface. An array of n-shaped traces marks the existence of counter-rotating, streamwise-oriented vortices just before the laminar separation line. Their interaction with thc laminar boundary layer and with the separation line is briefly described. An example of the intermittent excerpt of their influence through the laminar separation line is reported.

Item URL in elib:https://elib.dlr.de/110125/
Document Type:Article
Additional Information:Physics of Fluids 28, 124101 (2016); published online l December 2016; Published by the AIP Publishing
Title:Global and local skin friction diagnostics from TSP surface patterns on anunderwater cylinder in crossflow
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Miozzi, MassimoCNR-INSEAN, Via di Vallerano 139, 00128 Rome,ItalyUNSPECIFIED
Capone, AlessandroCNR-INSEAN, Via di Vallerano 139, 00128 Rome,ItalyUNSPECIFIED
Di Felice, Fabiocnr-insean istituto nazionale studi ed esperienze di architettura navale, via di vallerano 139, 00128 rome, italyUNSPECIFIED
Klein, ChristianChristian.Klein (at) dlr.deUNSPECIFIED
Liu, Tianshuwestern michigan university, klamazoo, mi 49008UNSPECIFIED
Journal or Publication Title:Physics of Fluids
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1063/1.4968525
Publisher:American Institute of Physics (AIP)
Keywords:TSP, cylinder, crossflow, skin friction
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
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Experimental Methods
Deposited By: Bachmann, Barbara
Deposited On:06 Jan 2017 13:52
Last Modified:23 Jan 2020 04:20

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