Effects of the quiescent core in turbulent channel flow on transport and clustering of inertial particles

The existence of a quiescent core (QC) in the center turbulent channel flows was demonstrated recent experimental and numerical studies. QC-region, which is characterized by relatively uniform velocity magnitude weak turbulence levels, occupies about 40% cross-section at Reynolds numbers Re? ranging from 1000 to 4000. influence QC region its boundaries on transport accumulation inertial particles has never been investigated before. Here, we first demonstrate that unidentifiable Re?=180, before an in-depth exploration particle-laden flow Re?=600 performed. spheres exhibited tendency accumulate preferentially high-speed regions within QC, i.e. contrary well-known concentration low-speed streaks near-wall region. particle wall-normal distribution, quantified means Voronoï volumes number concentrations, varied abruptly across QC-boundary vortical structures appeared as void areas due centrifugal mechanism. QC-boundary, localized strong shear layer, barrier, hindered. Nevertheless, statistics conditioned QC-frame show mean outside towards core, whereas tended migrate wall. Such upward downward motions are driven similar fluid parcels. present results exerts substantial particles, practical relevance high-Reynolds flow.