On the parameters of common settling velocity models for porous sediment aggregates

The settling behavior of sediment aggregates is a critical factor influencing the transport of fine-grained sediment in riverine and marine environments. Due to the small size and fragile structure of cohesive sediment aggregates, direct measurement of their porosity and permeability is challenging....

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Main Authors: Alexander Metelkin, Bernhard Vowinckel
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2025-06-01
Series:International Journal of Sediment Research
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Online Access:http://www.sciencedirect.com/science/article/pii/S1001627925000022
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author Alexander Metelkin
Bernhard Vowinckel
author_facet Alexander Metelkin
Bernhard Vowinckel
author_sort Alexander Metelkin
collection DOAJ
description The settling behavior of sediment aggregates is a critical factor influencing the transport of fine-grained sediment in riverine and marine environments. Due to the small size and fragile structure of cohesive sediment aggregates, direct measurement of their porosity and permeability is challenging. While porosity often is estimated using settling velocity relations, permeability is frequently overlooked. The current study examines the impact of considering non-negligible permeability on the properties of flocs. Aggregate properties are compared by calibrating experimental data to two settling models in a dilute regime: one assumes a fractal structure of aggregates and neglects permeability, while the other assumes constant porosity and permeability. The current results demonstrate that both models describe the experimental data of highly porous aggregates with similar accuracy. Aggregate dynamics are further investigated in more complex flow conditions using numerical simulations applying a volume penalization method to geometrically resolve flocs. The behavior of permeable and impermeable flocs is compared in dense suspension regimes and during dilute settling in density-stratified environments. The current findings reveal that permeability significantly influences settling dynamics in complex scenarios and should be considered when determining aggregate properties.
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spelling doaj-art-c3edf14b3fee42179ffa78ca731718cd2025-08-20T01:50:30ZengKeAi Communications Co., Ltd.International Journal of Sediment Research1001-62792025-06-0140341242510.1016/j.ijsrc.2025.01.002On the parameters of common settling velocity models for porous sediment aggregatesAlexander Metelkin0Bernhard Vowinckel1Institute of Urban and Industrial Water Management, Technische Universität Dresden, Bergstraße 66, Dresden, 01069, Germany; Leichtweiß-Institut for Hydraulic Engineering and Water Resources, Technische Universität Braunschweig, Beethovenstraße 51A, Braunschweig, 38106, Germany; Corresponding author. Institute of Urban and Industrial Water Management, Technische Universität Dresden, Bergstraße 66, Dresden 01069, Germany.Institute of Urban and Industrial Water Management, Technische Universität Dresden, Bergstraße 66, Dresden, 01069, Germany; Leichtweiß-Institut for Hydraulic Engineering and Water Resources, Technische Universität Braunschweig, Beethovenstraße 51A, Braunschweig, 38106, GermanyThe settling behavior of sediment aggregates is a critical factor influencing the transport of fine-grained sediment in riverine and marine environments. Due to the small size and fragile structure of cohesive sediment aggregates, direct measurement of their porosity and permeability is challenging. While porosity often is estimated using settling velocity relations, permeability is frequently overlooked. The current study examines the impact of considering non-negligible permeability on the properties of flocs. Aggregate properties are compared by calibrating experimental data to two settling models in a dilute regime: one assumes a fractal structure of aggregates and neglects permeability, while the other assumes constant porosity and permeability. The current results demonstrate that both models describe the experimental data of highly porous aggregates with similar accuracy. Aggregate dynamics are further investigated in more complex flow conditions using numerical simulations applying a volume penalization method to geometrically resolve flocs. The behavior of permeable and impermeable flocs is compared in dense suspension regimes and during dilute settling in density-stratified environments. The current findings reveal that permeability significantly influences settling dynamics in complex scenarios and should be considered when determining aggregate properties.http://www.sciencedirect.com/science/article/pii/S1001627925000022Flocculated aggregatesCohesive sedimentsHindered settlingDensity-stratified settling
spellingShingle Alexander Metelkin
Bernhard Vowinckel
On the parameters of common settling velocity models for porous sediment aggregates
International Journal of Sediment Research
Flocculated aggregates
Cohesive sediments
Hindered settling
Density-stratified settling
title On the parameters of common settling velocity models for porous sediment aggregates
title_full On the parameters of common settling velocity models for porous sediment aggregates
title_fullStr On the parameters of common settling velocity models for porous sediment aggregates
title_full_unstemmed On the parameters of common settling velocity models for porous sediment aggregates
title_short On the parameters of common settling velocity models for porous sediment aggregates
title_sort on the parameters of common settling velocity models for porous sediment aggregates
topic Flocculated aggregates
Cohesive sediments
Hindered settling
Density-stratified settling
url http://www.sciencedirect.com/science/article/pii/S1001627925000022
work_keys_str_mv AT alexandermetelkin ontheparametersofcommonsettlingvelocitymodelsforporoussedimentaggregates
AT bernhardvowinckel ontheparametersofcommonsettlingvelocitymodelsforporoussedimentaggregates