Sand-turbulence interaction in a high-Reynolds-number turbulent boundary layer under net sedimentation conditions

Particle–fluid–wall interaction of inertial spherical particles in a turbulent boundary layer

“…Fong et al 2019) sweep events crucially contribute to the turbophoretic drift that produces a multi-fold increase in near-wall concentration. In horizontal particle-laden flows, by contrast, the near-wall concentration has been found to be smaller than what predicted by the Rouse-Prandtl equilibrium theory (Kiger & Pan 2002;Zhu et al 2019;Berk & Coletti 2020). In § 3.6 we will show this to be the case also in the present configuration.…”

“…In horizontal particle-laden flows, by contrast, the near-wall concentration has been found to be smaller than what predicted by the Rouse–Prandtl equilibrium theory (Kiger & Pan 2002; Zhu et al. 2019; Berk & Coletti 2020). In § 3.6 we will show this to be the case also in the present configuration.…”

“…2012; Zhu et al. 2019; Berk & Coletti 2020). This is in contrast with configurations in which gravity does not participate to the wall-normal transport: in no-gravity simulations (e.g.…”

“…This indicates that sweeps weakly influence the descent of particles towards the wall, while ejections are a key factor in lifting the particles away from the wall. The prevalence of fluid ejection over sweeps in influencing particle transport was reported by previous studies focused on heavy particles suspended in horizontal wall-bounded flows over a wide range of physical parameters (Kiger & Pan 2002;van Hout 2011;Li et al 2012;Zhu et al 2019;Berk & Coletti 2020). This is in contrast with configurations in which gravity does not participate to the wall-normal transport: in no-gravity simulations (e.g.…”

Transport of inertial particles in high-Reynolds-number turbulent boundary layers

“…Kind (1992) reported concentrations smaller than the power-law fit in the outer region and linked it to positive (upward) vertical fluxes, leading to (3.12). Vice versa, under net sedimentation, Zhu et al (2019) recently reported a sharp increase of concentration above the power-law profile in the outer region of a particle-laden turbulent boundary layer. They also found smaller near-wall concentration than predicted by the power-law profile, and so did Kiger & Pan (2002).…”