We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Settling and drafting of spheres in quiescent fluids in microplastic-relevant regimes
AI summary Read the abstract
Scientists studying how microplastic particles sink in water found that when particles trail behind one another, they can speed up by up to 68%—essentially "drafting" like cyclists in a race. This means clusters of microplastics may sink faster and behave differently than current models predict, which matters because it affects where these tiny pollutants end up accumulating in oceans, lakes, and ultimately the food chain we rely on for seafood and drinking water.
The hydrodynamic settling of microplastic particles is yet to be explored in-depth, particularly in multiple-particle systems where wake interactions may affect settling dynamics. Here, we present an experimental study investigating the settling of spherical particles (∼1.92 mm, 1300 kg m−3) across a transitional particle Reynolds number range (Rep=6–185), relevant to microplastic transport. Using a dual-camera back-lit shadow-imaging system and Particle Tracking Velocimetry, we quantify single-particle terminal velocities and analyze pairwise interactions. Our findings reveal that trailing particles accelerate when entering the wake of a leading particle, with peak enhancements up to 68% above the single-particle terminal velocity. Interaction cases are characterized based on vertical and lateral spacing. In the key observed interaction pattern, drafting begins at a vertical distance of approximately two particle diameters and is accompanied by coupled lateral motion, indicating two-way interaction. These results demonstrate that particle–particle coupling during the drafting stage is stronger and more complex than predicted by classical models, and suggest that even weakly inertial microplastics can experience enhanced settling due to interparticle proximity. This work provides a foundation for improved predictive modeling of microplastic transport in aquatic environments.
More Papers Like This
Microplastics settle more quickly when near one another
AI summary Read the abstract
New research finds that tiny plastic particles sink faster when they're clustered near each other, rather than floating alone. This matters because how fast microplastics settle affects where they end up in water systems—including in the fish and seafood we eat, and potentially in our drinking water—so understanding their behavior helps scientists predict where plastic pollution accumulates and how it might reach us.
Coupled CFD-DEM modelling to assess settlement velocity and drag coefficient of microplastics
AI summary Read the abstract
Researchers used computational fluid dynamics coupled with particle simulations to model how the size, shape, and density of microplastics affect their settling velocity and drag in water. Accurate physical models of microplastic behavior are essential for predicting where particles accumulate in rivers, lakes, and the ocean.
Settling Velocities of Small Microplastic Fragments and Fibers
AI summary Read the abstract
Researchers precisely measured the settling speeds of over 4,000 small microplastic particles in water and found that existing prediction models designed for larger microplastics do not work well for these tiny fragments and fibers. The settling speed depends on each particle's size, density, and shape, with the smallest particles sinking extremely slowly. Understanding how quickly microplastics settle in water is important because it determines how far they travel and how long they remain available to be consumed by aquatic organisms that humans may eventually eat.
Microplastic-sediment aggregation increases microplastic settling velocity to values comparable to those of pure sediment flocs.
AI summary Read the abstract
When tiny plastic bits stick to clumps of natural sediment in rivers, they sink about 10 times faster, settling much like normal sediment does. This means microplastics likely build up in the same muddy hotspots where sediment naturally piles up, which could help scientists predict where plastic pollution accumulates in waterways that supply our drinking water and food sources.
Settling behaviors of microplastic disks in water
AI summary Read the abstract
Researchers investigated the settling behavior of microplastic disk particles in water, finding that lighter disks sink in straight vertical paths while denser disks follow oscillating zigzag trajectories — differences that significantly influence microplastic transport and distribution in aquatic environments.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.