How does two-way coupling modify particle settling and the role of multiscale preferential sweeping?

For one-way coupled (1WC) flows, Tom & Bragg ( J. Fluid Mech. , vol. 871, 2019, pp. 244–270) advanced the analysis of Maxey 174, 1987, 441–465), which applied to weakly inertial particles, particles arbitrary inertia, and new theoretical result revealed role that different scales play in preferential sweeping mechanism leads enhanced particle settling turbulent flows. Monchaux Dejoan Phys. Rev. Fluids 2, 2017, 104302) showed using direct numerical simulations that, while for low loading effect two-way coupling (2WC) on global flow statistics is weak, 2WC enables drag fluid their vicinity down with them, significantly enhancing settling, they argued suppresses mechanism. We explore this further by considering impact contribution made eddies sizes settling. In agreement Dejoan, we show even loading, strongly enhances how modifies from scales. However, contrary study, remains important particular, both 1WC enhancement due turbulence dominated contributions straining regions flow, but case, these also leading an compared case.