Particle Data Management Software for 3DParticle Tracking Velocimetry and
                        Related Applications – The Flowtracks Package

Meller, Yosef; Liberzon, Alex

doi:10.5334/jors.101

Cited by 12 publications

(7 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Instead, we post-processed the trajectories using the position-velocity space-linking algorithm 67 . The trajectory data were filtered and differentiated using the standard method of OpenPTV 63,68 . This included fitting a second-order polynomial to a window of N frames for each three-dimensional trajectory.…”

Section: Post Processingmentioning

confidence: 99%

See 1 more Smart Citation

Extended 3D-PTV for direct measurements of Lagrangian statistics of canopy turbulence in a wind tunnel

Shnapp

Shapira²,

Peri

et al. 2019

Sci Rep

Self Cite

View full text Add to dashboard Cite

Direct estimation of Lagrangian turbulence statistics is essential for the proper modeling of dispersion and transport in highly obstructed canopy flows. However, Lagrangian flow measurements demand very high rates of data acquisition, resulting in bottlenecks that prevented the estimation of Lagrangian statistics in canopy flows hitherto. We report on a new extension to the 3D Particle Tracking Velocimetry (3D-PTV) method, featuring real-time particle segmentation that outputs centroids and sizes of tracer particles and performed on dedicated hardware during high-speed digital video acquisition from multiple cameras. The proposed extension results in four orders of magnitude reduction in data transfer rate that enables to perform substantially longer experimental runs, facilitating measurements of convergent statistics. The extended method is demonstrated through an experimental wind tunnel investigation of the Lagrangian statistics in a heterogeneous canopy flow. We observe that acceleration statistics are affected by the mean shear at the top of the canopy layer and that Lagrangian particle dispersion at small scales is dominated by turbulence in the wake of the roughness elements. This approach enables to overcome major shortcomings from Eulerian-based measurements which rely on assumptions such as the Taylor’s frozen turbulence hypothesis, which is known to fail in highly turbulent flows.

show abstract

Section: Post Processingmentioning

confidence: 99%

“…The cutoff frequency of this low-pass filter was estimated to be f c = 150 Hz. Post-processing was conducted using the OpenPTV post-processing package, called Flowtracks 68 . It includes operations such as storing, handling and manipulating capabilities of vast amounts of data through a sophisticated application of the HDF5 format.…”

Section: Post Processingmentioning

confidence: 99%

Extended 3D-PTV for direct measurements of Lagrangian statistics of canopy turbulence in a wind tunnel

Shnapp

Shapira²,

Peri

et al. 2019

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…Almost the entire 3D-PTV post-processing is accomplished using the open source software OpenPTV, [54][55][56] which was originally developed at ETH Zürich 57,58 and is still further being improved by an international team of developers (including the current first author). The resulting particle trajectories are then further processed using in-house scripts, in which a least-squares Savitzky-Golay smoothing filter 59 is applied to the OpenPTV trajectory results.…”

Section: Details About the 3d-ptv Implementationmentioning

confidence: 99%

Lagrangian study of the particle transport past a lateral, open-channel cavity

et al. 2021

View full text Add to dashboard Cite

This paper presents a Lagrangian laboratory study of the passive tracer transport in and around a lateral, open-channel (square) cavity. Using 3D-particle tracking velocimetry (PTV), the trajectories of neutrally buoyant seeding particles are measured and analyzed to investigate the processes governing the particle exchanges between the cavity and the adjacent main stream for a selected subcritical flow condition. The tracked particles are classified using a Lagrangian approach based on their start and end positions, i.e., the cavity or the main stream region. Next, the spatial distribution of the particles at the main stream-cavity interface is analyzed to distinguish the typical transport processes of the different particle classes and identify preferential zones of net particle inflow, net particle outflow, and local zigzagging across the interface. Finally, this paper investigates the influence of the zigzag motion of particles on the (net) mass exchange coefficient. Derived from the same 3D-PTV dataset, a comparison between the common Eulerian (velocity-based) and Lagrangian mass exchange coefficients suggests that the transverse velocity method overestimates the net exchange significantly because of the particle zigzag motions.

show abstract

“…The video images are recorded and stored using the Norpix StreamPix high speed digital recording software (https://www.norpix.com/products/streampix/streampix.php). The calibration and tracking analysis to obtain the 3D trajectories is performed using the opensource Openptv software (https://www.openptv.net/) (Lthi et al, 2005;Mark et al, 2010) with flowtracks processing software (Meller & Liberzon, 2016).…”

Section: Particles Trajectories Analysismentioning

confidence: 99%

Laboratory Measurements of the Wave‐Induced Motion of Plastic Particles: Influence of Wave Period, Plastic Size and Plastic Density

2020

View full text Add to dashboard Cite

The amount of plastic in the aquatic environment is rapidly growing, with plastic litter having been reported in almost every marine environment. Understanding plastic dispersion is a key knowledge gap for plastic litter management and cleaning. It is widely assumed that the main source of plastic litter to the oceans is terrestrial and, therefore, the dominant plastic pathway from land sources to the ocean is via coastal regions. However, although there is relatively good knowledge on how the plastic particles move by oceanic currents, it is not clear how the plastic particles are transported by highly nonlinear coastal waves (see van Sebille et al., 2020, for a recent review on the physical plastic transport). Indeed, most of the existing global numerical models predicting plastic fluxes do not explicitly consider the plastic motion in coastal regions including the potential plastic beaching (i.e., plastic being washed ashore) (Neumann et al., 2014). The hydrodynamics controlling the motion of plastic in intermediate and shallow water is dominated by nonlinear gravity waves propagating toward the shoreline (wave motions and wave-induced currents). A particle floating on the free surface of a periodic gravity wave experiences a net drift in the direction of wave propagation termed Stokes drift (Stokes, 1847). The Stokes drift velocity is explained by the difference between the average Lagrangian velocity experienced by the particle and the average Eulerian flow velocity of the fluid (Longuet-Higgins, 1953; van den Bremer & Breivik, 2017). The Stokes drift is a second order velocity (Longuet-Higgins, 1953) of smaller magnitude than the magnitude of the wave orbital motion but,

show abstract

Particle Data Management Software for 3DParticle Tracking Velocimetry and Related Applications – The Flowtracks Package

Cited by 12 publications

References 6 publications

Extended 3D-PTV for direct measurements of Lagrangian statistics of canopy turbulence in a wind tunnel

Extended 3D-PTV for direct measurements of Lagrangian statistics of canopy turbulence in a wind tunnel

Lagrangian study of the particle transport past a lateral, open-channel cavity

Laboratory Measurements of the Wave‐Induced Motion of Plastic Particles: Influence of Wave Period, Plastic Size and Plastic Density

Contact Info

Product

Resources

About