<div class="csl-bib-body">
<div class="csl-entry">Alipour, M., De Paoli, M., & Soldati, A. (2022). Influence of Reynolds number on the dynamics of rigid, slender and non-axisymmetric fibres in channel flow turbulence. <i>Journal of Fluid Mechanics</i>, <i>934</i>, 1–27. https://doi.org/10.1017/jfm.2021.1145</div>
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dc.identifier.issn
0022-1120
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/20336
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dc.description.abstract
We investigate experimentally the dynamics of non-axisymmetric fibres in channel flow turbulence, focusing specifically on the importance of the fibre size relative to the flow scales. To this aim, we maintain the same physical size of the fibres and we increase the shear Reynolds number. Experiments are performed in the TU Wien Turbulent Water Channel for three values of shear Reynolds number, namely 180, 360 and 720. Fibres are slender - length to diameter ratio of 120 - rigid, curved and neutrally buoyant particles and their shape ranges from low curvature - almost straight fibres - to moderate curvature. In all cases, fibre size remains small compared with the channel height (≤1.5%). Three-dimensional and time-resolved recordings of the laser-illuminated measurement region are obtained from four high-speed cameras and used to infer fibre dynamics. With the aid of multiplicative algebraic reconstruction techniques, fibre position, orientation, velocity and rotation rates are determined. Our measurements span over the half-channel height, from wall to centre, and allow a complete characterisation of the fibre dynamics in all regions of the flow. Specifically, we measure fibre preferential distribution and orientation. We observe that the fibre dynamics is always influenced by their curvature. Through a comparison between measurements of the near-wall dynamics of the fibres and the near-wall dynamics of the flow, we identify a causal relationship between fibre velocity and orientation, and the near-wall turbulence dynamics. Finally, we have been able to provide original measurements of the tumbling rate of the fibres, for which we report the influence of fibre curvature. We underline that our measurements confirm previous findings obtained in numerical and experimental works.
en
dc.language.iso
en
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dc.publisher
CAMBRIDGE UNIV PRESS
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dc.relation.ispartof
Journal of Fluid Mechanics
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dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
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dc.subject
channel flow
en
dc.subject
particle/fluid flow
en
dc.title
Influence of Reynolds number on the dynamics of rigid, slender and non-axisymmetric fibres in channel flow turbulence