On the existence and formation of multi-scale particle streaks in turbulent channel flows

• DOI: 10.1017/jfm.2022.8
• Publication Date: 2022-01-26T11:16:41Z
• Authors: Yucheng Jie; Zhiwen Cui; Chunxiao Xu; Lihao Zhao
• Keywords: Stokes number; Particle (ecology); Particle-Laden Flows

Direct numerical simulations of particle-laden turbulent channel flows at friction Reynolds number $Re_\tau$ from $600$ to $2000$ have been performed examine the near-wall particle streaks. Different well-observed small-scale streaks in turbulence low , present results show large-scale through computational domain formed for relatively high-inertia particles high . Transferred by sweep and ejection events ( $Q^-$ ), these preferentially accumulate regions beneath low-speed flow observed logarithmic region. The corresponding Stokes numbers are associated with lifetime structures, which increases as grows. a typical $St_\nu \approx 30$ mainly driven structures buffer layer, whose is approximately $30$ viscous time unit. Therefore, we propose new structure-based normalized different scales. relevant scales that control formation parameterized number. (large-scale) most prominent when buffer-layer approaches unity. findings reveal governed scales, inertia respond efficiently respect translational motion.