A volumetric 3D measurement tool for velocity field diagnostics in microgravity experiments

Stüer, Heinrich; Maas, Hans‐Gerd; Virant, M.; Becker, Joachim

doi:10.1088/0957-0233/10/10/311

Cited by 13 publications

(9 citation statements)

References 11 publications

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“…Alternatively, multiple pinhole photography (Kieft et al, 2002;Maas et al, 1993;Moroni et al, 2003;Ott and Mann, 2000;Stuer et al, 1999;Virant and Dracos, 1997) and its variants (Pereira and Gharib, 2002) can be used for 3-D tracking of particles. The increased depth of focus required by this method is inherently coupled to reduced resolution and the need for bright illumination.…”

Section: Comparison With Other Techniquesmentioning

confidence: 99%

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography

Malkiel

Sheng

Katz

et al. 2003

Journal of Experimental Biology

125

101

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SUMMARY Digital in-line holography is used for measuring the three-dimensional(3-D) trajectory of a free-swimming freshwater copepod Diaptomus minutus, and simultaneously the instantaneous 3-D velocity field around this copepod. The optical setup consists of a collimated He-Ne laser illuminating a sample volume seeded with particles and containing several feeding copepods. A time series of holograms is recorded at 15 Hz using a lensless 2Kx2K digital camera. Inclined mirrors on the walls of the sample volume enable simultaneous recording of two perpendicular views on the same frame. Numerical reconstruction and matching of views determine the 3-D trajectories of a copepod and the tracer particles to within pixel accuracy(7.4 μm). The velocity field and trajectories of particles entrained by the copepod have a recirculating pattern in the copepod's frame of reference. This pattern is caused by the copepod sinking at a rate that is lower than its terminal sinking speed, due to the propulsive force generated by its feeding current. Consequently, the copepod sees the same fluid, requiring it to hop periodically to scan different fluid for food. Using Stokeslets to model the velocity field induced by a point force, the measured velocity distributions enable us to estimate the excess weight of the copepod(7.2×10-9 N), its excess density (6.7 kg m-3) and the propulsive force generated by its feeding appendages(1.8×10-8 N).

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Section: Comparison With Other Techniquesmentioning

confidence: 99%

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography

Malkiel

Sheng

Katz

et al. 2003

Journal of Experimental Biology

125

101

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“…Specifically, we study the applicability of classic models for conservative tracer transport IDagan, 1989; Gelhat, 1993; Edwards and What we report next are efforts, via a 3-D particle tracking velocimetry (3D-PTV) scanning technique [Stuer et al, 1999], to obtain quantitatively and nondestructively, the trajectories of tracer particles within a porous medium, which is homogeneous on the bench scale but heterogeneous on the pore scale. While we do not do so here, a slight generalization of the experimental approach can be applied to media Which are heterogeneous on any scale.…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional particle tracking velocimetry studies of the transition from pore dispersion to Fickian Dispersion for homogeneous porous media

Moroni¹,

Cushman²

2001

Water Resources Research

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Abstract. Fickian models developed to simulate transport in homogeneous porous media consider the flux of the contaminant species to be proportional to the concentration gradient via a constant dispersion tensor. When a solute has traveled sufficient distance or time, the mean square displacement may begin to grow linearly with time. We define the point at which the mean square displacement goes linear as the Darcy-scale Fickian limit. Prior to reaching this limit we say we are in the regime of pore-scale dispersion. In this paper we examine the transition from pore-scale dispersion to Fickian dispersion via three-dimensional particle tracking velocimetry (3D-PTV) in matched refractive index porous media. From the trajectories obtained via 3D-PTV we have computed the mean square displacements, velocity distributions, velocity correlation, and classical dispersion tensors. These data indicate the transverse components of the Darcy-scale dispersion tensor trend toward zero and that the longitudinal components go Fickian after approximately six pore diameters have been traversed.

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“…The 3D position is again analyzed through the same procedure to acquire the information for the next time step. The present work uses this method via an algorithm developed and obtained from ETH Zurich (Swiss Federal Institute of Technology) 21, 25. This method allows detecting the 3D particle positions in adjacent time steps, which when linked together produce trajectories of the particle and can be further analyzed to obtain the 3D velocity field, and even particle accelerations.…”

Section: D Particle Image Reconstructionmentioning

confidence: 99%

“…The approach presented requires optical access to the flow, and it describes a time resolved volumetric measurement technique capable of individually and simultaneously tracking up to ∼400 particles in a stirred tank to provide their Lagrangian trajectories. This technique, known as three‐dimensional particle tracking velocimetry (3D‐PTV) has been recently introduced in other fields of research for its comprehensive flow measurement capabilities to follow individual particles as a function of time while providing 3D particle positions and velocities 19–23. The 3D‐PTV system is based on the acquisition and processing of a sequence of images, of a particle seeded flow, from several cameras with different orientations.…”

Section: Introductionmentioning

confidence: 99%

A 4D imaging tool for Lagrangian particle tracking in stirred tanks

Cheng

Díez

2010

AIChE Journal

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A time-resolved volumetric 3D particle tracking tool is presented for mixing in stirred tanks studies and its capabilities are explored in a low Reynolds number custom-made stirred tank. The technique provides a Lagrangian description of particles in the flow resolving their 3D trajectories, velocities, and acceleration. The optimization of the system allowed, for the first time, tracking $400 particles at a time in an imaged volume (60 mm Â 60 mm Â 50 mm) in the stirred tank. The system was validated in a 1-D piston-driven flow and by comparing the measurements with a 2D-particle image velocimetry system in a stirred tank. Results show the advantages of this technique to understand particle dynamics. Sample measurements illustrated that small changes in the stirrer configuration produced an unexpected variety of particle trajectories which were classified according to their path shape and location. Particle velocities and Lagrangian accelerations provided new insights into their mixing process.

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A volumetric 3D measurement tool for velocity field diagnostics in microgravity experiments

Cited by 13 publications

References 11 publications

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography

The three-dimensional flow field generated by a feeding calanoid copepod measured using digital holography

Three‐dimensional particle tracking velocimetry studies of the transition from pore dispersion to Fickian Dispersion for homogeneous porous media

A 4D imaging tool for Lagrangian particle tracking in stirred tanks

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