Bedload transport and bedforms migration under sand supply limitation

Vah, Mélanie; Jarno, Armelle; Bot, Sophie Le; Ferret, Yann; Marin, François

doi:10.1007/s10652-020-09738-6

Cited by 10 publications

(13 citation statements)

References 47 publications

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“…A honeycomb‐shaped screen was installed upstream of the flume (Figure 1a) to ensure uniform flow conditions. The flume walls were made of transparent glass to allow visual observations of the bed surface from the sides of the flume and the use of optical measurement techniques (Khoury et al., 2019; Vah, Jarno, Le Bot, et al, 2020).…”

Section: Experimental Setup and Tests Conditionsmentioning

confidence: 99%

A visual method for threshold detection of sediment motion in a flume experiment without human interference

Vah

Alaa

Jarno

et al. 2022

Earth Surf Processes Landf

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An experimental investigation of the entrainment threshold of sediment grains conducted in a non‐tiltable flume is reported and an original processing method based on image correlation suitable for detection of sediment threshold of motion is presented. Unlike existing visual measurement methods, the proposed method is not affected by the individual judgement of the experimentalists, which may strongly impact the estimation of incipient motion. Three entrainment thresholds were exhibited. The method highlighted a first threshold for very low shear stress conditions that was interpreted as a nascent movement threshold. The other two thresholds of motion were related to distinct stages of surface mobility of the bed: one related to bedload threshold and the other to bedform threshold. Series of tests were first performed to study the sensitivity of the method to different parameters: angle of view of the camera, size of the image and acceleration rate of the linear ramp of flow velocity. A ratio of the image surface and the grain surface equal to 3000 was found to be the minimum size to perform reliable estimations of entrainment thresholds for all the sediments in the range of 0.328–2.648 mm tested. It was the only condition for the method to work. Once the method was validated, tests were performed with homogeneous sands and compared to results based on reference‐based and visual methods. The correlation method yields similar values for the bedload threshold to those obtained from reference‐based methods. Thus it could be an alternative to other methodologies by the simplicity of its implementation, precision, no requirement for human interference and direct correlation between threshold velocity and bed mobility without extrapolation.

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Section: Experimental Setup and Tests Conditionsmentioning

confidence: 99%

A visual method for threshold detection of sediment motion in a flume experiment without human interference

Vah

Alaa

Jarno

et al. 2022

Earth Surf Processes Landf

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“…Numerous researchers have used experimental tests in laboratory flumes with unidirectional, steady and uniform currents (e.g. Bennett and Best, 1995;Best and Kostaschuk, 2002;McLean et al, 1994;Vah et al, 2020) to develop empirical relationships between dunes and their controlling environmental variables.…”

Section: Introductionmentioning

confidence: 99%

“…Cheng et al, 2004;Villard and Church, 2005;Bartholdy et al, 2005;, or (2) for exploring the relationship between the field dune migration rates and the empirical/numerical bedload transport rates (e.g. Hoekstra et al, 2004;Kostaschuk et al, 2004;Masselink et al, 2009;Williams et al, 2006;Vah et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Morphodynamics of intertidal dune field in a mixed wave-tide environment: Case of Baie de Somme in Eastern English Channel

et al. 2021

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…Les structures sédimentaires en disponible limité ne sont que très peu étudiées par rapport aux structures sédimentaires en disponible illimité alors que les conditions de disponible Thème 2 -Dynamique sédimentaire sableux limité sont communes à la fois en rivière et en mer. Quelques études expérimentales ont été menées en canaux inclinés représentant des conditions fluviales (TUIJNDER et al, 2009 ;DREANO et al, 2010) et en canal à fond non incliné (VAH et al, 2020). L'objectif de cette étude est de comparer qualitativement et quantitativement les longueurs d'ondes à l'équilibre de séries de tests réalisées avec un disponible sédimentaire variable.…”

Section: Introductionunclassified

“…Le nombre de Reynolds est défini par Re=Ud/ν avec U la vitesse moyenne du courant et ν la viscosité cinématique du fluide (ν=1.10 -6 m 2 /s). Le paramètre de Shields sur fond plat est défini tel que θ'= * /((s-1)gD50, avec * la vitesse de frottement au fond dans le cas d'un fond plat et basé sur le diamètre des grains(VAH et al, 2020). Le paramètre de Shields critique pour la mise en mouvement des sédiments, θc, est estimé en utilisant la formulation de Soulsby (SOULSBY, 1997) : θc=0,3/(1+1,2 * )+0,055(1-exp(-0,02 * )),…”

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Modélisation physique de l’impact du disponible sédimentaire sur la morphologie des structures sédimentaires en courant seul

Vah¹,

Jarno²,

Bot³

et al. 2020

XVIèmes Journées, Le Havre

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Les expériences ont été menées dans un canal à courant à fond horizontal. Le disponible sédimentaire initial varie dans une gamme allant d'extrêmement limité à illimité. Une recirculation des sédiments est assurée de manière à conserver un disponible constant tout au long de chaque test. Dans le cas d'un sable moyen bien trié, l'étude de l'évolution des longueurs d'onde des structures sédimentaires à l'équilibre en fonction du disponible sédimentaire pour différentes conditions hydrodynamiques initiales est proposée. Une augmentation de la longueur d'onde est constatée quand le disponible sédimentaire augmente. L'irrégularité des structures sédimentaires est aussi discutée. Les longueurs d'onde à l'équilibre en disponible infini sont comparées avec la littérature et sont en bon accord sauf dans le cas de formes de petite échelle surimposées à des structures de plus grande échelle.

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Bedload transport and bedforms migration under sand supply limitation

Cited by 10 publications

References 47 publications

A visual method for threshold detection of sediment motion in a flume experiment without human interference

A visual method for threshold detection of sediment motion in a flume experiment without human interference

Morphodynamics of intertidal dune field in a mixed wave-tide environment: Case of Baie de Somme in Eastern English Channel

Modélisation physique de l’impact du disponible sédimentaire sur la morphologie des structures sédimentaires en courant seul

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