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61,005 resultsShowing papers similar to Settling velocity of submillimeter microplastic fibers in still water
ClearControlling factors of microplastic fibre settling through a water column
Using particle tracking velocimetry, researchers measured the settling velocity of 683 polyester microplastic fibers and found that fiber length, curliness, and settling orientation all control descent through water. Curly fibers settled up to 1.75 times slower than straight fibers of equal length, and the low settling velocities (0.1 to 0.55 mm/s) suggest microplastic fibers are prone to biological flocculation and prolonged suspension in the water column.
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.
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.
Settling Velocities of Small Microplastic Fragments and Fibers
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.
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.
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.
Additional data for "Settling Velocities of Small Microplastic Fragments and Fibers"
This data repository provides raw settling velocity measurements for small microplastic fragments and fibers, supporting a publication on their transport behavior in water. Settling velocity data is critical for modeling where microplastics deposit in rivers, lakes, and ocean sediments.
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.
Settling velocities of microplastics with different shapes in sediment-water mixtures
Researchers studied how the shape of microplastic particles affects how quickly they sink in water containing suspended sediment. They found that fibers and films settle much more slowly than fragments and pellets, and that sediment in the water significantly slows the settling of all microplastic types. These findings are important for predicting where microplastics accumulate in lakes, rivers, and oceans.
Settling velocity of microplastic particles having regular and irregular shapes
Researchers measured how quickly microplastic particles of various shapes settle through water, testing 66 different particle types including spheres, cylinders, fibers, and irregular fragments. They found that particle shape significantly affects settling speed, with fibers and flat shapes sinking more slowly than spheres of the same size. The study provides new equations for predicting where microplastics end up in oceans and waterways based on their shape.
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.
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.
Settling Velocities of Environmentally Weathered Plastic Fibers from the Mekong River in Southeast Asia
Researchers measured the settling velocities of environmentally weathered plastic fibers collected from the Mekong River, finding that weathering significantly alters fiber density and shape, affecting how fibers sink and accumulate in aquatic sediments.
Settling velocity of microplastic particles of regular shapes
This study measured the sinking velocities of spherical, cylindrical, and filament-shaped microplastic particles ranging from 0.5 to 5 mm, finding that shape strongly determines how quickly particles settle through the water column. Understanding settling behavior is essential for modeling how microplastics are transported and deposited in marine environments.
A new model for the terminal settling velocity of microplastics
A new empirical model for the terminal settling velocity of microplastics was developed and validated using 1,343 experimental measurements covering a range of particle shapes and materials. The model improves predictions of microplastic sedimentation rates, which are critical for understanding how plastic particles are transported and deposited in water bodies.
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.
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.
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.
Sediment-Water Interfaces as Traps and Sources of Microplastic Fragments and Microfibers─Insights from Stream Flume Experiments
Researchers used controlled stream flume experiments to study how microplastic fibers and fragments settle into riverbed sediments. They found that lower water flow speeds caused faster deposition, with the effect being strongest for fibers, and that traditional settling equations significantly underestimate how microplastics actually behave near the streambed. The findings improve our understanding of where and how microplastics accumulate in rivers.
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.
Mobility and retention of microplastic fibers and irregular plastic fragments in fluvial systems: an experimental flume study
Researchers conducted experimental flume studies to compare the mobility and retention of microplastic fibres and irregularly shaped plastic fragments in fluvial systems. The study found that particle shape strongly influences transport behaviour, with fibres exhibiting greater mobility and distinct retention patterns compared to irregular fragments, highlighting the need to move beyond spherical particle models in microplastic transport research.
Microfiber behavior in turbulence and in quiescent conditions: insights from 3D high-speed measurements
Researchers investigated the settling dynamics of microplastic fibers with high aspect ratios under turbulent and quiescent airflow conditions, using 3D high-speed measurements to show that existing drag models fail to accurately predict settling velocities of these anisotropic curved fibers with diameters of 10-100 micrometers.
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.
Settling behaviors of microplastic disks in acceleration fall
Researchers studied the settling behavior of disk-shaped microplastics during free-fall in water, using high-speed imaging to track the orientation and velocity of particles as they descended. Disk-shaped particles exhibited oscillating and tumbling motions that slowed settling compared to spheres of equivalent mass, with implications for predicting microplastic transport and deposition in aquatic environments.