Papers

61,005 results
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Article Tier 2

Improved Settling Velocity for Microplastic Fibers: A New Shape-Dependent Drag Model

A new shape-dependent drag model was developed to improve the accuracy of settling velocity predictions for microplastic fibers, addressing a major limitation of existing drag models that significantly underpredict fiber settling in aquatic environments.

2021 Environmental Science & Technology 85 citations
Article Tier 2

Low Reynolds Number Settling of Cylindrical Rods with Various Geometries in a Quiescent Fluid

Researchers experimentally investigated the settling behaviour of curved, V-shaped, U-shaped, and S-shaped cylindrical rods at low Reynolds numbers to improve models of atmospheric microplastic fibre transport, conducting experiments with millimeter-scale metal rods spanning aspect ratios from 10 to 120. The study found that fibre geometry significantly affects settling trajectories and drag compared to simplified sphere or straight-cylinder approximations used in current atmospheric transport models.

2025 York University Digital Library (York University)
Article Tier 2

Full rotational dynamics of plastic microfibers in turbulence

Researchers conducted Lagrangian experiments on elongated, large aspect-ratio curved plastic microfibers near the Kolmogorov length scale in turbulence, tracking their three-dimensional orientation optically to characterize rotational dynamics and settling behavior that govern microplastic transport and dispersion in the ocean.

2024 arXiv (Cornell University)
Article Tier 2

Terminal Settling Velocity of Cylindrical Rods with Various Geometries Applicable to Atmospheric Microplastics

Researchers measured how the shape of cylindrical microplastic fibers affects their settling speed through air, finding that curved and V-shaped fibers fall significantly faster than straight ones — up to 57% faster for V-shaped rods — which matters for predicting how airborne microplastics disperse in the atmosphere.

2024 Proceedings of the ... International Conference on Fluid Flow, Heat and Mass Transfer
Article Tier 2

Settling velocity of submillimeter microplastic fibers in still water

The settling velocity of 519 submillimeter microplastic fibers (300-600 micrometers long) was measured in still water, finding that settling rates vary considerably by fiber length and orientation, informing models of microplastic fiber transport and deposition in aquatic systems.

2023 The Science of The Total Environment 15 citations
Article Tier 2

A physics-based and orientation-aware method for the direct calculation of  the settling speed of prolate spheroidal particles in the atmosphere : theoretical basis and comparison to laboratory and CFL data

Researchers developed a physics-based, orientation-aware method for calculating the settling speed of prolate spheroidal particles such as microplastic fibres in the atmosphere, grounding the approach in theoretical drag and orientation models rather than purely empirical fits and validating it against laboratory and CFD data.

2025
Article Tier 2

Settling of nonuniform cylinders at intermediate Reynolds numbers

This study investigated the settling behavior of non-uniform cylindrical particles at intermediate Reynolds numbers, providing new data on how particle shape and aspect ratio influence drag and settling velocity. The findings are relevant to predicting the transport and deposition of microplastic fibers in water.

2024 Physical Review Fluids 7 citations
Article Tier 2

Towards realistic predictions of microplastic fiber transport in aquatic environments: Secondary motions

Researchers developed an improved drag model for predicting microplastic fiber settling in water by incorporating secondary motions including tumbling and oscillation in addition to the standard drag forces. Secondary motions profoundly affect settling trajectories and deposited positions, and the new model outperforms existing approaches that neglect these behaviors.

2022 Water Research 50 citations
Article Tier 2

Gravitational settling of microplastic fibers: experimental results and implications for global transport

This study measured the gravitational settling velocities of microplastic fibers and found that their non-spherical shape causes them to settle much more slowly than spheres of the same volume. Current atmospheric transport models that assume spherical particles significantly underestimate how long fibers remain airborne. These results have important implications for predicting how far microplastic fibers can travel before depositing.

2023
Article Tier 2

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.

2020 1 citations
Article Tier 2

Settling processes of cylindrical microplastics in quiescent water: A fully resolved numerical simulation study

Using a lattice Boltzmann numerical model, this study simulated how cylindrical microplastic fibers sink through still water and identified a critical shape ratio (aspect ratio ~0.93–0.94) at which settling behavior shifts dramatically. Understanding how fiber shape governs sinking speed is key to predicting where MP fibers accumulate in aquatic environments and how long they remain suspended.

2023 Marine Pollution Bulletin 12 citations
Article Tier 2

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.

2025
Article Tier 2

Full Rotational Dynamics of Plastic Microfibers in Turbulence

Researchers conducted experiments on the rotational dynamics of elongated plastic microfibers in turbulent conditions. The study provides new data on how these microplastic fibers spin and tumble in turbulence, which is important for understanding the motion, settling, and dispersion patterns of microplastics in ocean environments.

2024 Physical Review Letters 12 citations
Article Tier 2

Prediction of the settlement of submillimeter microplastic fibers in still water

Using fluid dynamics simulations validated by experiments, researchers modeled how submillimeter synthetic textile fibers sink through still water, finding that standard drag equations (Stokes law) apply when fibers orient horizontally. They developed an improved drag model that accounts for fiber orientation, enabling more accurate predictions of where microfibers ultimately settle in lakes, rivers, and oceans. Knowing where fibers accumulate helps identify which aquatic habitats and organisms face the greatest exposure.

2024 Environmental Technology & Innovation 3 citations
Article Tier 2

Effects of Biofilms and Particle Physical Properties on the Rising and Settling Velocities of Microplastic Fibers and Sheets

Researchers investigated how biofilms and physical properties affect the rising and settling velocities of microplastic fibers and sheets, finding that biofouling significantly altered vertical transport dynamics depending on particle shape and size.

2022 Environmental Science & Technology 89 citations
Article Tier 2

Obstacle-induced lateral dispersion and nontrivial trapping of flexible fibers settling in a viscous fluid

This paper is not relevant to microplastics; it is a fluid dynamics study investigating how flexible fibers settle in a viscous fluid with obstacles, examining trapping and gliding behaviors relevant to fiber sorting applications.

2023 Physical Review Fluids 10 citations
Article Tier 2

On the fully coupled dynamics of flexible fibres dispersed in modulated turbulence

Researchers investigated the dynamics of flexible elastic fibers freely suspended in turbulent flow using direct numerical simulations, finding that fiber inertia, flexibility, and turbulence intensity interact to produce complex deformation and preferential concentration behaviors relevant to microplastic fiber transport.

2022 Journal of Fluid Mechanics 21 citations
Article Tier 2

The atmospheric settling of commercially sold microplastics

Researchers measured the gravitational settling velocities of commercially available glitter microplastics (0.1-3 mm nominal diameter) and synthetic fibers (1.2-5 mm length) in air, finding that non-spherical shapes cause complex settling behaviors that deviate substantially from spherical particle models used in atmospheric transport models.

2025
Article Tier 2

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.

2024 Zenodo (CERN European Organization for Nuclear Research)
Article Tier 2

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.

2021 Environmental Science and Pollution Research 92 citations
Article Tier 2

Torques on curved atmospheric fibres

Researchers derived a theoretical model for how planar curved atmospheric fibers settle in quiescent air, finding that fluid-inertia torques can align asymmetric fibers at oblique angles relative to gravity — consistent with recent laboratory observations. The model demonstrates that inertial alignment is a general and important factor governing the atmospheric transport of asymmetric particles such as curved microplastic fibers and ash particles.

2024 arXiv (Cornell University)
Article Tier 2

Predicted settling velocity of sampled MPFs

This is a dataset of predicted settling velocities for microplastic fibers using a newly proposed model — not a standalone research article.

2023 Figshare
Article Tier 2

Inertial settling of an arbitrarily oriented cylinder in a quiescent flow : from short-time to quasi-steady motion

This study modeled the inertial settling behavior of cylindrical particles — which can represent microplastic fibers — falling through still water. Researchers derived mathematical expressions for how cylinders orient and accelerate during settling at both short and long time scales. Understanding how fiber-shaped microplastics settle is important for predicting where they accumulate in aquatic environments.

2023 arXiv (Cornell University)
Article Tier 2

Effects of Shape and Size on Microplastic Atmospheric Settling Velocity

Researchers measured atmospheric settling and horizontal drift velocities of various microplastic shapes and sizes in controlled settling chambers, providing empirical data needed to improve atmospheric transport models that explain how microplastics reach remote environments.

2023 Environmental Science & Technology 39 citations