TY - JOUR

T1 - Blood, lead and spheres: A hindered settling equation for sedimentologists based on metadata analysis

AU - Baas, Jaco H.

AU - Baker, Megan L.

AU - Buffon, Patricia

AU - Strachan, Lorna J.

AU - Bostock, Helen C

AU - Hodgson, David

AU - Eggenhuisen, Joris T.

AU - Spychala, Yvonne T.

N1 - Funding Information: The authors are grateful to Equinor Norway for funding part of this research through a grant to Baas and Baker, which also partially contributed to Buffon’s visit to the Hydrodynamics Laboratory at Bangor University from the Federal University of Rio Grande do Sul. The authors also wish to thank the TNA access to EPOS multi‐scale laboratory facilities programme at Utrecht University, which funded the hindered settling metadata analysis, and related experimental work intended for a separate paper. William Morgan kindly assisted in the hindered settling experiments. An earlier version of this paper benefitted from the detailed comments by an anonymous reviewer and the Associate Editor.

PY - 2022/6/20

Y1 - 2022/6/20

N2 - A revision of the popular equation of Richardson and Zaki (1954a, Transactions of the Institute of Chemical Engineering, 32, 35–53) for the hindered settling of suspensions of non-cohesive particles in fluids is proposed, based on 548 data sets from a broad range of scientific disciplines. The new hindered settling equation enables predictions of settling velocity for a wide range of particle sizes and densities, and liquid densities and viscosities, but with a focus on sediment particles in water. The analysis of the relationship between hindered settling velocity and particle size presented here shows that the hindered settling effect increases as the particle size decreases, for example, a 50% reduction in settling velocity is reached for 0.025 mm silt and 4 mm pebbles at particle concentrations of 13% and 25% respectively. Moreover, hindered settling starts to influence the settling behaviour of sediment particles at volumetric concentrations of merely a few per cent. For example, the particle settling velocity in flows that carry 5% silt is reduced by at least 22%. These observations suggest that hindered settling greatly increases the efficiency of natural flows to transport sediment particles, but also particulate carbon and pollutants, such as plastics, over large distances.

AB - A revision of the popular equation of Richardson and Zaki (1954a, Transactions of the Institute of Chemical Engineering, 32, 35–53) for the hindered settling of suspensions of non-cohesive particles in fluids is proposed, based on 548 data sets from a broad range of scientific disciplines. The new hindered settling equation enables predictions of settling velocity for a wide range of particle sizes and densities, and liquid densities and viscosities, but with a focus on sediment particles in water. The analysis of the relationship between hindered settling velocity and particle size presented here shows that the hindered settling effect increases as the particle size decreases, for example, a 50% reduction in settling velocity is reached for 0.025 mm silt and 4 mm pebbles at particle concentrations of 13% and 25% respectively. Moreover, hindered settling starts to influence the settling behaviour of sediment particles at volumetric concentrations of merely a few per cent. For example, the particle settling velocity in flows that carry 5% silt is reduced by at least 22%. These observations suggest that hindered settling greatly increases the efficiency of natural flows to transport sediment particles, but also particulate carbon and pollutants, such as plastics, over large distances.

KW - hindered settling

KW - metadata analysis

KW - particle fall velocity

UR - http://www.scopus.com/inward/record.url?scp=85124625919&partnerID=8YFLogxK

U2 - 10.1002/dep2.176

DO - 10.1002/dep2.176

M3 - Article

VL - 8

SP - 603

EP - 615

JO - The Depositional Record

JF - The Depositional Record

SN - 2055-4877

IS - 2

ER -