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Large Scale Adverse Pressure Gradient Turbulent Boundary Investigation by means of PIV and PTV

Buchmann, N. A. and Cierpka, Christian and Knopp, Tobias and Schanz, Daniel and Schröder, Andreas and Hain, R. and Kähler, Christian (2014) Large Scale Adverse Pressure Gradient Turbulent Boundary Investigation by means of PIV and PTV. 17th Internatinal Symposium on Application Laser Techniques to Fluid Mechanics, 07. - 10. July 2014, Lisbon, Portugal.

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Official URL: http://ltces.dem.ist.utl.pt/lxlaser/lxlaser2014/finalworks2014/papers/03.7_5_210paper.pdf

Abstract

subjected to a streamwise adverse pressure gradient Δp+ =ν/(ρu3 τ) dp/dx. However the statistically averaged behaviour of turbulent boundary layers subjected to adverse pressure gradients (i.e.Δp+ >0) is still an poorly understood. For zero-pressure gradient boundary layers the log-law u+ = 1/Ki log(y+) + Bi gives a proper description of the mean velocity at sufficiently large Reτ [7]. However, for adverse pressure gradient flows the log-law breaks down and a socalled half-power law or modified log-law with a functional depends on Δp+ may exist [4, 6]. Another open point is the spatial (and temporal) organisation of the coherent large and small-scale structures. While these aspects are far better understood for zero-pressure gradient boundary layers, there is little information for wall-bounded flows with streamwise adverse pressure gradients. In order to study the coherent flow structures, higher-order turbulent statistics and wall shear stress characteristics in a turbulent boundary layer subjected to adverse pressure gradients an experiment that builds on the recent progress in Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) is carried out. The experiment is designed such that the flow starts with a fully developed zeropressure gradient turbulent boundary layer and subsequently the flow experiences a streamwise adverse pressure gradient. The imposed pressure gradient is such that the streamwise flow development is slow with no history effects, but sufficiently large to cause changes from the universal log-law (e.g. Δp+ ≫0.015).

Item URL in elib:https://elib.dlr.de/89903/
Document Type:Conference or Workshop Item (Speech)
Additional Information:Paper-Nr.: 03.7_5_210, Book of Abstracts
Title:Large Scale Adverse Pressure Gradient Turbulent Boundary Investigation by means of PIV and PTV
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Buchmann, N. A.Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, 85577 Neubiberg, GermanyUNSPECIFIED
Cierpka, ChristianUniBW MünchenUNSPECIFIED
Knopp, Tobiastobias.knopp (at) dlr.deUNSPECIFIED
Schanz, Danieldaniel.schanz (at) dlr.deUNSPECIFIED
Schröder, Andreasandreas.schroeder (at) dlr.deUNSPECIFIED
Hain, R.UniBW MünchenUNSPECIFIED
Kähler, ChristianUniBw MünchenUNSPECIFIED
Date:2014
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:p. 1
Series Name:Conference Proceedings online
Status:Published
Keywords:Turbulent Boundary Layer, Adverse Pressure Gradient, PIV, long-range micro PIV, Wall Shear Stress
Event Title:17th Internatinal Symposium on Application Laser Techniques to Fluid Mechanics
Event Location:Lisbon, Portugal
Event Type:international Conference
Event Dates:07. - 10. July 2014
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
Institute of Aerodynamics and Flow Technology > C²A²S²E - Center for Computer Applications in AeroSpace Science and Engineering
Deposited By: Micknaus, Ilka
Deposited On:30 Jul 2014 17:01
Last Modified:20 Oct 2014 14:22

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