We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Settling velocity of microplastics in turbulent open-channel flow
AI summary Read the abstract
Researchers studied how microplastic particles settle in turbulent river-like flow conditions compared to still water and developed a new formula to predict their behavior. They found that turbulence altered settling velocities by as much as 26% depending on particle properties, with larger, heavier particles being less influenced by water turbulence. The findings are important for building better models of how microplastics are transported and distributed in rivers and other flowing waterways.
The settling behavior of microplastics (MPs) plays a pivotal role in their transport and fate in aquatic environments, but the dominant mechanisms and physics governing the settling of MPs in rivers remain poorly understood. To gain mechanistic insights into the velocity lag of MPs in an open-channel flume under different turbulent flow conditions, an experimental study was conducted using three types of MPs: polystyrene, cellulose acetate, and acrylic, of sphere-shaped particles with diameters ranging from 1 mm to 5 mm. A particle tracking technique was employed to record and analyze the MPs velocity within turbulent flows. The results showed a variation in the vertical settling velocity of MPs ω ranging from -26 % to +16 %, when compared to their counterparts in still water (ω). A new formula for the drag coefficient (C) of MP particles was developed by introducing the suspension number (u/ω). The developed C formula was used to calculate the resultant velocity lag V, with a mean relative error of 16 % compared with the measured values. Further, the study highlighted that the MPs with large Stokes numbers are mainly driven by their own inertia and turbulence has less influence on their settling behavior. This study is crucial for understanding the settling behavior of MPs in turbulent flows and developing their transport and fate models for MPs in riverine systems.
More Papers Like This
Modeling the settling and resuspension of microplastics in rivers: Effect of particle properties and flow conditions
AI summary Read the abstract
Researchers developed a mathematical model to simulate how microplastics of different shapes settle and resuspend in rivers, moving beyond the common assumption that all particles are spherical. They found that turbulence has a complex effect, sometimes keeping particles suspended longer and sometimes accelerating their settling, depending on flow conditions. The model reveals that particle shape significantly influences where microplastics end up in river systems.
Response of microplastic particles to turbulent flow: An experimental study
AI summary Read the abstract
Using controlled flume experiments, researchers studied how turbulent flow conditions affect the transport and settling behavior of microplastic particles with varied shapes and densities, finding that turbulence intensity and particle morphology interacted to determine suspension and deposition patterns.
Microplastic dynamics within turbulence for improved modelling and monitoring strategies
AI summary Read the abstract
This study developed improved models for predicting microplastic distribution and transport within river systems, accounting for turbulence effects and the exchange between suspended load and bedload. The authors identified that existing sediment transport models fail to capture the behavior of low-density plastic particles in turbulent flow. More accurate models are needed to predict where microplastics accumulate in rivers and estimate their flux to the ocean.
Entrainment and vertical mixing of aquatic microplastics in turbulent flow: The coupled role of particle size and density
AI summary Read the abstract
Researchers conducted laboratory flume experiments to study how turbulence affects the vertical mixing and entrainment of microplastic particles of different sizes and densities. Both particle size and polymer density significantly influenced mixing behavior, with smaller and denser particles more responsive to turbulent structures, informing models of microplastic transport in rivers and coastal waters.
Study of the influence of fluvial dynamics on the distribution and transport of microplastics.
AI summary Read the abstract
Researchers studied how fluvial dynamics including flow velocity, turbulence, and river geomorphology influence the distribution and transport of microplastics in river systems. River hydrodynamics were found to be major determinants of where microplastics accumulate and how far they travel, with implications for predicting contamination patterns in river catchments.
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.