Abstract

Cohesive sediment forms flocs of various sizes and structures in the natural turbulent environment. Understanding flocculation is critical in accurately predicting sediment transport and biogeochemical cycles. In addition to aggregation and breakup, turbulence also reshapes flocs toward more stable structures. An Eulerian–Lagrangian framework has been implemented to investigate the effect of turbulence on flocculation by capturing the time-evolution of individual flocs. We have identified two floc reshaping mechanisms, namely breakage-regrowth and restructuring by hydrodynamic drag. Surface erosion is found to be the primary breakup mechanism for strong flocs, while fragile flocs tend to split into fragments of similar sizes. Aggregation of flocs of sizes comparable to or greater than the Kolmogorov scale is modulated by turbulence with lower aggregation efficiency. Our findings highlight the limiting effects of turbulence on both floc size and structure.

Details

Title
Persistent reshaping of cohesive sediment towards stable flocs by turbulence
Author
Yu, Minglan 1 ; Yu, Xiao 1 ; Mehta, Ashish J. 1 ; Manning, Andrew J. 2 ; Khan, Faisal 3 ; Balachandar, S. 4 

 University of Florida, Department of Civil and Coastal Engineering, Gainesville, USA (GRID:grid.15276.37) (ISNI:0000 0004 1936 8091) 
 University of Florida, Department of Civil and Coastal Engineering, Gainesville, USA (GRID:grid.15276.37) (ISNI:0000 0004 1936 8091); HR Wallingford, Wallingford, UK (GRID:grid.12826.3f) (ISNI:0000 0000 8789 350X) 
 Texas A&M University, Department of Chemical Engineering, College Station, USA (GRID:grid.264756.4) (ISNI:0000 0004 4687 2082) 
 University of Florida, Department of Mechanical and Aerospace Engineering, Gainesville, USA (GRID:grid.15276.37) (ISNI:0000 0004 1936 8091) 
Pages
1760
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2771199328
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.