Giurgiu, V., Caridi, G. C. A., De Paoli, M., & Soldati, A. (2023, November 21). Measurements of spinning and tumbling rates of Kolmogorov scale micro-plastic fibres [Conference Presentation]. 76th Annual Meeting of the Division of Fluid Dynamics, Washington D.C., United States of America (the).
E322 - Institut für Strömungsmechanik und Wärmeübertragung E322-01 - Forschungsbereich Strömungsmechanik
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Datum (veröffentlicht):
21-Nov-2023
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Veranstaltungsname:
76th Annual Meeting of the Division of Fluid Dynamics
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Veranstaltungszeitraum:
19-Nov-2023 - 21-Nov-2023
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Veranstaltungsort:
Washington D.C., Vereinigte Staaten von Amerika
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Keywords:
Turbulence; Microplastics; Fibres
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Abstract:
We measure the effect of the wall-normal location of micro-plastic fibres on spinning and tumbling rates in wall-bounded turbulence. The measurements are performed in a turbulent water channel at shear Reynolds number of 720. Fibres are 1.2mm long and 10μm in diameter (aspect ratio 120). Their length ranges from 4 to 12 Kolmogorov length scales. They are neutrally buoyant, inertial-less, and rigid in these flow conditions.
Six high-speed cameras image the fibres at the channel centre and in a near-wall region. We employ and further refine a technique of tomographic fibre reconstruction and tracking. Their curved shape is used to define a fibre-fixed reference frame and measure its time-resolved orientation. Thus measurements of tumbling and spinning rates are enabled. We provide a discussion about the uncertainty on the rotation rates based on their shape and angular displacement between time-steps. Based on converged statistics, we observed that the mean and mean square spinning are higher than tumbling rates at both channel centre and near-wall region. Our results are original, because previous measurements are restricted to rotation rates of longer rods in homogeneous isotropic turbulence or to tumbling rates only.
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Projekttitel:
Mikrofasern in turbulenter Strömung im offenen Kanal: P 35505-N (FWF - Österr. Wissenschaftsfonds)
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Projekt (extern):
FSE S3 HEaD PRIN
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Projektnummer:
1619942002 2017RSH3JY
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Forschungsschwerpunkte:
Environmental Monitoring and Climate Adaptation: 100%