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3D Lagrangian Particle Tracking with Multi-Pulse Shake-The-Box in Turbulent Boundary Layer Flows at High Reynolds Numbers

Novara, Matteo and Schanz, Daniel and Geisler, Reinhard and Gesemann, Sebastian and Voss, Christina and Schröder, Andreas (2019) 3D Lagrangian Particle Tracking with Multi-Pulse Shake-The-Box in Turbulent Boundary Layer Flows at High Reynolds Numbers. In: 17th European Turbulence Conference ETC 2019 (227), 1 - 1. 17th European Turbulence Conference ETC 2019, 03. - 06. Sept. 2019, Torino, Italy.

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Abstract

The recent introduction of the Multi-Pulse Shake-The-Box technique (MP-STB [3]) extended the capabilities of the Shake-The-Box (STB [4]) 3D Lagrangian particle tracking (LPT) algorithm in terms of applicable flow velocity. In particular, the MP-STB allows for 3D LPT investigations at velocities relevant for industrial and aerodynamic applications in relatively large volumes where the adoption of a time-resolved recording strategy would result in significant compromises in terms of spatial range or resolution (in order to limit the particle displacement between subsequent recordings). Multi-pulse sequences are obtained by synchronizing multiple illumination systems to generate bursts of laser pulses (typically four) where the time separation can be freely adjusted down to less than a microsecond (e.g. for supersonic applications). A 3D imaging system consisting of dual-frame cameras is adopted, where each frame is double-exposed to record the four pulses [2]; the MP-STB technique makes use of an iterative approach to overcome the limitations posed by the short observation time offered by the multi-pulse recording sequence, and allows for the reconstruction of individual four-pulse particle tracks in 3D [3]. The acquisition of long sequences of four-pulse recordings at low frequency (10-15Hz) enables the evaluation of flow statistics. In the present study, the MP-STB technique is employed for the investigation of turbulent boundary layer (TBL) flows at relatively high Reynolds numbers. A TBL at 15 m/s (Reθ ≈ 10; 000) is investigated in the SWG facility at DLR Göttingen; approximately 95; 000 individual tracks are reconstructed within the 80×120×10 mm^3 domain for each four-pulse recording. Spatial gradients, as well as the instantaneous 3D pressure field, are evaluated by means of the FlowFit data assimilation algorithm [1] (fig.1-left). A TBL with adverse pressure gradient (APG) at 29 m/s (Reθ ≈ 30; 000) is investigated in the atmospheric wind tunnel of the University of Armed Forces in Munich; both planar PIV and MP-STB in a 80 × 90 × 7 mm^3 domain are employed; the direct comparison of the results in terms of turbulent fluctuations (fig.1-right) highlights the higher spatial resolution of the LPT approach which, unlike PIV, does not suffer from the signal modulation caused by the finite size of the cross-correlation window. In the final presentation the MP-STB processing technique will be introduced together with the main parameters affecting its performances. Moreover, results regarding the TBL structure and flow statistics (e.g. TBL profiles, two-point correlations) will be presented.

Item URL in elib:https://elib.dlr.de/129532/
Document Type:Conference or Workshop Item (Speech)
Additional Information:NUMERICAL METHODS AND DATA ANALYSIS• Session 5
Title:3D Lagrangian Particle Tracking with Multi-Pulse Shake-The-Box in Turbulent Boundary Layer Flows at High Reynolds Numbers
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Novara, Matteomatteo.novara (at) dlr.deUNSPECIFIED
Schanz, Danieldaniel.schanz (at) dlr.deUNSPECIFIED
Geisler, Reinhardreinhard.geisler (at) dlr.deUNSPECIFIED
Gesemann, Sebastiansebastian.gesemann (at) dlr.deUNSPECIFIED
Voss, Christinachristina.voss (at) dlr.deUNSPECIFIED
Schröder, Andreasandreas.schroeder (at) dlr.dehttps://orcid.org/0000-0002-6971-9262
Date:September 2019
Journal or Publication Title:17th European Turbulence Conference ETC 2019
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:1 - 1
Editors:
EditorsEmail
Guido, BofettaUniversità di Torino
Daniela, TordellaPolitecnico di Torino
Series Name:Conference Proceedings online
Status:Published
Keywords:Lagrangian, 3D particle tracking, multi-pulse, Shake-The-Box, boundary layers
Event Title:17th European Turbulence Conference ETC 2019
Event Location:Torino, Italy
Event Type:international Conference
Event Dates:03. - 06. Sept. 2019
Organizer:Università degli studi di Torino, Politecnico di Torino
Institution:Deutsches Zentrum für Luft- und Raumfahrt e.V.
Department:AS-EXV
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 for Aerodynamics and Flow Technology > Experimental Methods, GO
Institute for Aerodynamics and Flow Technology > High Speed Configurations, GO
Deposited By: Micknaus, Ilka
Deposited On:11 Oct 2019 17:05
Last Modified:11 Oct 2019 17:05

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