Attached eddy-like particle clustering in a turbulent boundary layer under net sedimentation conditions

Zhu, Hang-Yu; Pan, Chong; Wang, Guohua; Liang, Yi-Rui; Ji, Xiaocang; Wang, Jinjun

doi:10.1017/jfm.2021.389

Cited by 16 publications

(31 citation statements)

References 62 publications

(123 reference statements)

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“…The difference is due to the particle volume fraction: in Zhu et al. (2021), the volume fractions are and , approximately one order of magnitude higher than the volume fraction in present experiment, .…”

Section: Cluster Identificationcontrasting

confidence: 56%

“…They could just as easily be associated with the sweeping events induced along the backbone of the hairpin packet, as argued by Zhu et al. (2021), and still obtain a similar velocity distribution due to the same induction process.…”

Section: Particle Velocities Within Clusterssupporting

confidence: 53%

“…These clusters are a bit larger than the typical size detected in previous studies; for instance, Zhu et al. (2021) reported the most probable Voronoi area as . The difference is due to the particle volume fraction: in Zhu et al.…”

Section: Cluster Identificationmentioning

confidence: 69%

“…The Voronoi approach has been recently applied by Zhu et al. (2021) to the experimental identification of particle clusters in the streamwise/wall-normal (–) plane of a TBL. They showed that particle clusters tend to reside on the downstream-inclined ridges of attached, streamwise (), low-momentum structures as a result of the high-strain associated with the near-wall, sweep-ejection process.…”

Section: Introductionmentioning

confidence: 99%

“…Zhu et al. (2021) also found inertial particles leading the fluid at , well beyond the viscous sublayer, but they suggested that the cause was particle advection by large-scale coherent structures which tend to exceed the local mean velocity. The idea that particles collect as a result of turbulent, coherent motions goes back to the work of Crowe et al.…”

Section: Introductionmentioning

confidence: 99%

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Spatial detection and hierarchy analysis of large-scale particle clusters in wall-bounded turbulence

2022

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Large-scale inertial particle clustering in a turbulent boundary layer (TBL) was investigated experimentally by two-colour particle-image velocimetry and particle-tracking velocimetry measurements in the wall-parallel plane of the log layer. The particle clusters were detected by Voronoi tessellation and a new application of a technique based on the spatial wavelet transform. Anisotropic wavelets spanning the range of measurable, large-scale particle clusters were applied to experimentally measured particle fields, and significance testing was used to identify hierarchies of particle clusters. Unlike the Voronoi tessellation, which primarily identified small-scale clusters, the wavelet technique also found a significant amount of anisotropic, large-scale clusters on the scale of the large-scale motions (LSMs) of the momentum field. The large-scale clusters were shown to be composed of a hierarchy of smaller clusters of varying degrees of isotropy. In addition to the cluster size distribution, the particle velocities within the clusters were studied as a function of cluster size. Larger clusters exhibited faster particle convection speeds, consistent with observations of the convection speeds of LSMs, thus providing additional evidence for the hypothesis that particles in the TBL accumulate on and are transported by large-scale, attached coherent structures.

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Section: Cluster Identificationcontrasting

confidence: 56%

Section: Particle Velocities Within Clusterssupporting

confidence: 53%

Section: Cluster Identificationmentioning

confidence: 69%