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dc.contributor.authorJie, Yucheng
dc.contributor.authorZhao, Lihao
dc.contributor.authorXu, Chunxiao
dc.contributor.authorAndersson, Helge Ingolf
dc.identifier.citationTheoretical and Applied Mechanics Letters. 2019, 9 (3), 212-214.nb_NO
dc.description.abstractAxis-symmetric spheroids, such as rod-like and disk-like particles, have been found to orient preferentially in near-wall turbulence by both experiment and numerical simulation. In current work we examined the orientation of inertialess spheroids in a turbulent channel flow at medium friction Reynolds number R eτ = 1000 given based on the half of channel height. Both elongated prolate spheroid and flat oblate spheroid are considered and further compared with the reference case of spherical particle. The statistical results show that in near wall region the prolate spheroids tend to align in the streamwise direction while the oblate spheroids prefer to orient in the wall-normal direction, which are consistent with earlier observation in low Reynolds number (R eτ = 180) wall turbulence. Around the channel center we found that the orientation of spheroids is not fully isotropic, even though the fluid vorticity are almost isotropic. The mechanism that gives rise to such particle orientations in wall-turbulence has been found to be related to fluid Lagrangian stretching and compression (Zhao and Andersson 2016). Therefore, we computed the left Cauchy-Green strain tensor along Lagrangian trajectories of tracer spheroids in current flow field and analyzed the fluid Lagrangian stretching and compression. The results indicated that, similar to the earlier observations, the directions of the Lagrangian stretching and compression in near-wall region are in the streamwise and wall-normal directions, respectively. Furthermore, cross over the channel the prolate spheroids aligned with the direction of Lagrangian stretching but oblate spheroids oriented with the direction of Lagrangian compression. The weak anisotropy of orientations of fluid Lagrangian stretching and compression observed at the channel center could be the reason for the aforementioned modest anisotropic orientation of spheroids in channel central region.nb_NO
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internasjonal*
dc.subjectAerosoler og partiklernb_NO
dc.subjectAerosols and particlesnb_NO
dc.titlePreferential orientation of tracer spheroids in turbulent channel flownb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.subject.nsiVDP::Fysikk: 430nb_NO
dc.subject.nsiVDP::Physics: 430nb_NO
dc.source.journalTheoretical and Applied Mechanics Lettersnb_NO
dc.relation.projectNotur/NorStore: NN2649Knb_NO
dc.relation.projectNorges forskningsråd: 250744nb_NO
dc.description.localcodeThis article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed.nb_NO
cristin.unitnameInstitutt for energi- og prosessteknikk

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Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivatives 4.0 Internasjonal