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Uncertainty Reduction of FlowFit Flow Field Estimation by Use of Virtual Particle

Ehlers, Frithjof and Schröder, Andreas and Gesemann, Sebastian (2019) Uncertainty Reduction of FlowFit Flow Field Estimation by Use of Virtual Particle. In: 13th International Symposium on Particle Image Velocimetry (208), pp. 345-354. 13th International Symposium on Particle Image Velocimetry, 22.-24.07.2019, Munich, Germany.

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Official URL: https://athene-forschung.unibw.de/128737?sortfield0=authors&sortfield1=&show_id=128912

Abstract

From experiments, data is available in the form of particle pictures from which particle tracks can be inferred by tracking techniques such as tomographic PTV or Shake-The-Box. But complete knowledge of the velocity field is sought on the basis of the scattered velocity and acceleration data. For this purpose different spatial interpolation algorithms were proposed, such asFlowFit and VIC+, which take Lagrangian particle track data (position, velocity and acceleration) as input and exploit known physical properties such as continuity and the Navier-Stokes equations for incompressible and uniform-density flows to reconstruct accurate and high resolution velocity, acceleration and pressure fields. The mentioned algorithms reach higher spatial resolutions beyond Nyquist than interpolation schemes that make use of the constraint of solenoidality only, due to the increased amount of data. We aim to develope a method in which virtual particles from previous reconstructions are advected into the following interpolation timestep with an individual weight dependend on (i) the Lagrangian correlation functions known from the track data and (ii) the local velocity gradient tensor as estimated. Usually, the time steps are about the size of the Kolmogorov time scale so the Lagrangian velocities and accelerations at two subsequent time instants are still significantly correlated. Therefore, a straightforward approach to combine the information of multiple reconstructions is to involve additional virtual particles into the reconstruction process that are advected with the estimated velocity and acceleration in order to act as information carrier between the reconstructed fields, thus enforcing consistency in time.

Item URL in elib:https://elib.dlr.de/130429/
Document Type:Conference or Workshop Item (Speech)
Additional Information:128912 Paper
Title:Uncertainty Reduction of FlowFit Flow Field Estimation by Use of Virtual Particle
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ehlers, Frithjoffrithjof.ehlers (at) dlr.deUNSPECIFIED
Schröder, Andreasandreas.schroeder (at) dlr.dehttps://orcid.org/0000-0002-6971-9262
Gesemann, SebastianSebastian.Gesemann (at) dlr.deUNSPECIFIED
Date:July 2019
Journal or Publication Title:13th International Symposium on Particle Image Velocimetry
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 345-354
Series Name:Conference Proceedings online
Status:Published
Keywords:Three-dimensional Lagrangian Particle Tracking (LPT), Shake-The-Box (STB), Jet, Turbulence
Event Title:13th International Symposium on Particle Image Velocimetry
Event Location:Munich, Germany
Event Type:international Conference
Event Dates:22.-24.07.2019
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
Deposited By: Micknaus, Ilka
Deposited On:21 Nov 2019 16:38
Last Modified:21 Nov 2019 16:38

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