title: Novel single Camera Techniques for 3D3C Lagrangian Trajectory Measurements in Interfacial Flows
creator: Voss, Björn Magnus
subject: ddc-530
subject: 530 Physics
description: This thesis presents two single camera Particle Streak Velocimetry (PSV) techniques that were purpose-built for the measurement of Lagrangian three-dimensional three-component (3D3C) flow information in the turbulent boundary layer of transparent interfaces. Both techniques are based on a particle streak extraction routine that enables a sub-pixel precise extraction of individual particle trajectories. A periodical intensity modulation of the illumination was implemented to increase the temporal resolution of the extracted Lagrangian trajectories. The achieved high spatial and temporal resolution enables quantitative measurements of Lagrangian flow characteristics in the interfacial region of turbulent flow fields. The first measurement technique, called bichromatic Particle Streak Velocimetry (bPSV), uses an absorbing dye and a two-wavelength LED illumination to resolve three-dimensional data that are needed for the extraction of 3D3C trajectories. In the second measurement technique the depth estimation is realized by means of a focused plenoptic camera that records long time exposure light fields. Both techniques were applied to measure interfacial flow fields in a turbulent Rayleigh-Bénard (RB) convection. On the basis of the Lagrangian particle trajectories obtained in the bPSV measurements, acceleration statistics and particle pair dispersion statistics were evaluated. A comparison of the Lagrangian acceleration distribution with two recently published models yielded good agreements. In the extracted Lagrangian particle pair dispersion, transitions between three turbulent regimes (i.e. the Batchelor regime, the Richardson-Obukhov (R-O) regime and the diffusive regime) were observed. 
date: 2012
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/13362/1/bvossDiss.pdf
identifier: DOI:10.11588/heidok.00013362
identifier: urn:nbn:de:bsz:16-opus-133624
identifier:   Voss, Björn Magnus  (2012) Novel single Camera Techniques for 3D3C Lagrangian Trajectory Measurements in Interfacial Flows.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/13362/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng