Energetic motions in turbulent partially filled pipe flow

Ng, Henry C-H ORCID: 0000-0003-4926-7622, Collignon, Emile, Poole, Robert J ORCID: 0000-0001-6686-4301 and Dennis, David JC ORCID: 0000-0003-0214-7885
(2021) Energetic motions in turbulent partially filled pipe flow. Physics of Fluids, 33 (2). 025101-025101.

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<jats:p>Turbulent partially filled pipe flow was investigated using stereoscopic particle imaging velocimetry in the cross-stream plane for a range of flow depths at a nominally constant Reynolds number of 30 000 (based on the bulk velocity and hydraulic diameter). Unlike full pipe flow, which is axisymmetric, the turbulent kinetic energy exhibits significant azimuthal (and radial) variation. Proper orthogonal decomposition (POD) of the fluctuating velocity field indicates that the leading-order POD modes occupy the “corners” where the free surface meets the pipe wall and that these modes, which are closely linked to the instantaneous cellular structure, contribute nearly a quarter of the overall turbulent kinetic energy. Spatial distributions of the large- and very-large-scale motions (LSMs/VLSMs) estimated from pseudo-instantaneous three-dimensional velocity fields reveal a preference for the sides (in close proximity to the free surface) and bottom quadrant of the pipe. That the LSMs and VLSMs are shown to populate a region spanning the width of the free surface, as well as the corners, strongly suggests that there is a dynamical connection between LSMs/VLSMs and the instantaneous cellular structures in turbulent partially filled pipe flow, which can explain the spatial redistribution of the turbulent kinetic energy.</jats:p>

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 09 Feb 2021 08:23
Last Modified: 08 Aug 2023 00:59
DOI: 10.1063/5.0031639
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3115364