Fully Developed Open Channel Flow Over Clusters of Freshwater Mussels Partially Buried in a Gravel Bed

T. Lazzarin; G. Constantinescu; H. Wu; D. P. Viero

doi:10.1029/2023WR035594

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Fully Developed Open Channel Flow Over Clusters of Freshwater Mussels Partially Buried in a Gravel Bed

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Fully Developed Open Channel Flow Over Clusters of Freshwater Mussels Partially Buried in a Gravel Bed

T. Lazzarin, G. Constantinescu, H. Wu and D. P. Viero

Water resources research, Vol.60(8), e2023WR035594

08/2024

DOI: 10.1029/2023WR035594

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Abstract

Abstract The present study uses results of eddy‐resolving numerical simulations to investigate the open channel flow over large clusters of freshwater mussels ( Unio elongatulus ) partially buried in a rough, gravel bed. The density of the mussels forming the array varies from 26 to 500 mussels/m 2 . The flow structure is analyzed at large distances from the leading edge of the mussel bed, where the flow can be considered fully developed. The effects of changing the mussel bed density, the filtering discharge, the burial level and the roughness of the bed surface in which mussels are burrowed, are investigated in terms of flow field, turbulent structures, drag forces, and bed shear stresses. It is found that strong interactions occur between energetic eddies generated by the larger gravels on the exposed bed surface and by the mussel shells. Simulations results show that for a burial depth close to 50% and a ratio between the average gravel size and the mussel protruding height of 0.13, the shell induced turbulence becomes dominant for mussel bed densities around 50 mussels/m 2 . The influence of the bed roughness becomes less relevant with increasing mussel density, as the generation of energetic eddies is mostly controlled by mussel‐to‐mussel interactions. For fixed bed roughness, burial level and filtering velocity, the mean streamwise drag force and the associated drag coefficient for the exposed part of each mussel decrease with increasing mussel density, even if strong variations are observed for individual mussels. For constant mussel bed density and burial level, the mean streamwise drag force and the mean drag coefficient decrease slightly with increasing bed roughness. Increasing the burial level decreases not only the drag forces but also the drag coefficients because of the more streamlined shape of the top of the mussels. Strong active filtering acts toward decreasing the mean streamwise force and the mean drag coefficient. The spanwise drag forces contribute significantly to the total drag force, especially for high mussel bed densities. Based on smooth bed calculations, bed‐averaged shear stresses are reduced in highly dense clusters. Key Points Mussel‐to‐mussel interactions are important for dense arrays and influence flow structure and turbulence Eddy resolving simulations showed that the effect of bed roughness become less significant with increasing mussel bed density In dense clusters of mussels, forces on the shells and bed shear stresses are reduced thus favoring mussel stability

freshwater mussels

mussel bed

turbulence

gravel bed

CFD

fully developed flow

Details

Title: Subtitle: Fully Developed Open Channel Flow Over Clusters of Freshwater Mussels Partially Buried in a Gravel Bed
Creators: T. Lazzarin - University of Padua
G. Constantinescu - University of Iowa
H. Wu - University of Iowa
D. P. Viero - University of Padua
Resource Type: Journal article
Publication Details: Water resources research, Vol.60(8), e2023WR035594
Publisher: AMER GEOPHYSICAL UNION
DOI: 10.1029/2023WR035594
ISSN: 0043-1397
eISSN: 1944-7973
Grant note: Italian National Research Programme PRIN: 2017SEB7Z8 CINECA: HP10COF04 N EAR Hydrologic Science Program of the US National Science Foundation: 1659518
This study was supported by Italian National Research Programme PRIN 2017, with the project 2017SEB7Z8 "IntEractions between hydrodyNamics flows and bioTic communities in fluvial Ecosystems: advancement in dischaRge monitoring and understanding of Processes Relevant for ecosystem sustaInability by the development of novel technologies with fIeld observatioNs and laboratory testinG (ENTERPRISING)." The CINECA award HP10COF04 N under the ISCRA initiative is acknowledged for the availability of high-performance computing resources and support. The authors gratefully acknowledge Prof. D. Termini from Univ. Palermo, Italy, for providing the digital reproduction of the gravel bed and the mussel shell used in the present work. Nicoletta Riccardi, permanent researcher at CNR-IRSA, is gratefully acknowledged for providing the mussel used in the experiments and valuable information on mussel anatomy and filtering activity. T. Lazzarin is sponsored by a PhD scholarship funded by the CARIPARO Foundation, and by a scholarship provided by the A. Gini foundation for his research period at IIHR-Hydroscience and Engineering, The University of Iowa, USA. G. Constantinescu and H. Wu acknowledge partial support from the EAR Hydrologic Science Program of the US National Science Foundation under Grant 1659518.
Language: English
Date published: 08/2024
Academic Unit: Civil and Environmental Engineering
Record Identifier: 9984695705402771

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