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 M.

AU - Eggenhuisen, Joris T.

AU - Spychala, Yvonne T.

N1 - no embargo upon publication

PY - 2022/6

Y1 - 2022/6

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 datasets from a broad range of scientific disciplines. The new hindered settlingequation 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 effectincreases as the particle size decreases, e.g., 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 fewpercent. 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 datasets from a broad range of scientific disciplines. The new hindered settlingequation 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 effectincreases as the particle size decreases, e.g., 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 fewpercent. 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

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 -