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Papers
61,005 resultsShowing papers similar to Impact of the Reynolds Numbers on the Velocity of Floating Microplastics in Open Channels
ClearContinuous Near-Bed Movements of Microplastics in Open Channel Flows: Statistical Analysis
Particle tracking velocimetry experiments in a laboratory flume showed that near-bed microplastic transport in open channels follows a normal streamwise velocity distribution, with transport behavior varying significantly by particle type and hydraulic conditions.
Plastic drift : Mapping the course of microplastic transport in turbulent riverine flows.
Researchers investigated the transport dynamics of 24 negatively buoyant microplastic particles across a spectrum of sizes, shapes, and densities using a 3D particle tracking system in turbulent open channel flow, generating 720 trajectories. They found that particle shape was the dominant determinant of transport behavior, with fibers tending to remain near the water surface at lower forward velocities while spheres stayed closer to the bed with higher forward velocities.
Incipient Motion of Exposed Microplastics in an Open-Channel Flow
Researchers experimentally determined the conditions needed to initiate microplastic movement in open-channel water flows, finding that standard sediment transport thresholds do not apply to microplastics and proposing a new predictive formula that reduces error from 55.6% to 12.3%.
Visualization of Buoyant MP motion in response to different flow velocities and bed types
Researchers visualized the movement of buoyant microplastic particles (lower density than water) in channels with different flow velocities and bed types. The experiments showed that these particles move along the water surface at velocities close to surface flow speed, making them highly mobile in rivers. This behavior helps explain why low-density microplastics like polyethylene are widely transported and dispersed in freshwater systems.
Plastic drift : Mapping the course of microplastic transport in turbulent riverine flows.
Researchers conducted laboratory experiments tracking the 3D trajectories of 24 negatively buoyant microplastic particles spanning a range of sizes, shapes, and densities in turbulent open channel flow, generating 720 trajectories to evaluate how well conventional sediment transport models apply to microplastics. Results revealed that the inherent variability in microplastic physical properties challenges direct application of sediment transport concepts to microplastic fate prediction in rivers.
Experimental study on the motion characteristics and critical hydraulic parameters of microplastics in a freshwater environment
Researchers conducted hydraulic flume experiments and force analyses to determine critical flow velocity thresholds for microplastic initiation, transport, and resuspension in freshwater environments, finding that settling velocities ranged from 0.05 to 0.17 m/s and that higher density, rougher surfaces, and flake-like shapes all increased the critical flow velocity required for microplastic movement.
Computational Analysis of Microplastics Hydrodynamics
Researchers developed a numerical model in Python and OpenFOAM to simulate microplastic particle dynamics in laminar open-channel flow, finding that particles smaller than 0.5 mm are unlikely to settle regardless of sphericity index, with results validated on a supercomputer.
Effect of Shape and Size on the Transport of Floating Particles on the Free Surface in a Natural Stream
Researchers used particle tracking velocimetry to study how shape and size affect the movement of floating particles on the turbulent free surface of a natural stream, finding that millimeter-scale spheres behaved differently from centimeter-scale irregular objects. Understanding particle transport mechanics is essential for predicting microplastic fate in river systems.
Mapping Microplastic Movement: A Phase Diagram to Predict Nonbuoyant Microplastic Modes of Transport at the Particle Scale
Researchers tracked 24 different types of nonbuoyant microplastic particles in turbulent open channel flow to understand how they are transported in aquatic environments. They found that microplastics move similarly to natural sediments through rolling, saltation, and suspension, but particle shape strongly influences transport behavior, with fibers staying closer to the water surface than spheres. The study introduces a new phase diagram for predicting microplastic transport modes based on flow conditions and particle properties.
Coupled CFD-DEM modelling to assess settlement velocity and drag coefficient of microplastics
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.
Numerical simulation and experimental study of microplastic transport under open channel shear flow: Roles of particle physical properties and flow velocities
Laboratory flume experiments and Lattice Boltzmann Method simulations showed that horizontal microplastic transport velocity increases with flow velocity while vertical velocity decreases, with particle density and concentration influencing transport behavior in open channel shear flow.
Response of microplastic particles to turbulent flow: An experimental study
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.
Three-Dimensional Settling Dynamics of Environmental Microplastics
Researchers measured the three-dimensional settling dynamics of environmental microplastic particles in water, including lateral drift, settling paths, and horizontal velocities—dimensions poorly understood beyond simple vertical settling rates. The findings are essential for developing accurate models of how MPs distribute across river channels and water columns.
Effect of Shape and Size on the Transport of Floating Particles on the Free Surface in a Meandering Stream
Using particle tracking in a field-scale meandering stream, researchers found that the shape and size of floating particles — including microplastics — significantly affect how they move with water currents. Irregularly shaped particles behave differently than spheres, which matters for predicting where plastic pollution accumulates in waterways.
Dynamics of microplastics bedload transport in turbulent open channel flows over smooth and rough beds
Researchers developed novel empirical formulas for predicting bedload transport layer thickness and velocity of microplastics in turbulent open-channel flows using 80 controlled flume experiments across diverse particle types and flow conditions. The new formula for bedload layer thickness reduced prediction error by 75% compared to existing sediment-based formulas, demonstrating the critical role of particle density and bed characteristics in shaping MP transport dynamics.
Computational Analysis of Microplastics Hydrodynamics in Laboratory Experiment
Researchers conducted computational simulations of microplastic hydrodynamics in an open channel using OpenFOAM with turbulent flow modelling, validating the simulation against laboratory experimental results and examining how particle properties influence settling behaviour.
Evidence of Microplastic Size Impact on Mobility and Transport in the Marine Environment: A Review and Synthesis of Recent Research
This review synthesized evidence on how microplastic particle size affects transport and dispersal in the marine environment, finding that size critically influences turbulent entrainment, settling velocity, and resuspension, analogous to well-established natural sediment transport dynamics.
Transport and accumulation of plastic particles on the varying sediment bed cover: Open-channel flow experiment
Researchers conducted open-channel flow experiments to study how various plastic particles of differing shape, size, density, and flexibility are transported and retained across sediment beds of varying grain size, finding that friction-driven retention zones consistently form at boundaries between finer and coarser sediments, offering a mechanism to explain the patchy distribution of microplastics in seafloor sediments.
Settling velocity of irregularly shaped microplastics under steady and dynamic flow conditions
The settling velocities of irregularly shaped microplastics were measured under both still water and dynamic flow conditions, finding that shape strongly affected settling speed and that turbulence caused non-spherical particles to orient and settle differently than spheres, with implications for predicting microplastic vertical transport in rivers and coastal waters.
Transport dynamics of microplastics from land to sea: the role of particle properties and stream morphology.
Researchers measured how particle properties including size, density, and polymer type interact with stream morphology to determine microplastic transport distances in 15 streams. Both plastic characteristics and stream structure independently influenced how far microplastics travel before settling, with implications for estimating fluxes to the ocean.
Understanding the dynamics of microplastics transport in urban stormwater runoff: Implications for pollution control and management
Researchers modeled how microplastics travel through urban stormwater runoff into water bodies. They found that a microplastic's shape, size, and density strongly influence whether it settles or floats during transport, and that local factors like street slope and surface friction significantly affect how quickly particles reach storm drains. The findings could help cities design better stormwater management strategies to capture microplastics.
Effect of Surface Waves on Settling and Drifting of Microplastic Particles: A Laboratory Experiment
Researchers conducted laboratory wave-channel experiments to study the trajectories, settling velocities, and drift velocities of microplastic particles of varying shapes (isometric, flat, elongated) under surface wave and wind-driven current conditions, finding terminal settling velocities of 1.0-3.8 cm/s in still fluid and characterizing how wave action modifies transport behavior.
Direct numerical simulation of the distribution of floating microplastic particles in an open channel flow
This study used direct numerical simulation to model the three-dimensional distribution of floating microplastic particles in open channel flow, providing quantitative predictions of how particle buoyancy, size, and turbulence interact to control microplastic concentration profiles in rivers.
Effects of Particle Properties on the Settling and Rise Velocities of Microplastics in Freshwater under Laboratory Conditions
Physical experiments quantified the settling and rise velocities of ~500 microplastic particles of varying shapes, sizes, and densities under controlled laboratory conditions, finding velocities ranging from 0.39 cm/s (settling polyamide fibers) to 31.4 cm/s (rising expanded polystyrene), with standard sediment transport formulas inadequate for fibers. The study provides empirical data needed to improve models of microplastic transport in rivers and lakes.