A laboratory examination of floc characteristics with regard to turbulent shearing

Manning, Andrew J.; Dyer, K.R.

doi:10.1016/s0025-3227(99)00013-4

Cited by 215 publications

(159 citation statements)

References 30 publications

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“…This behaviour is also modulated by sediment concentration because of the increase in inter-particle collisions and also increases the probability of aggregation. The diagram by Dyer has been confirmed by a number of experiments (van Leussen, 1994;Manning and Dyer, 1999;Verney et al, 2011) and field observations (Fettweis et al, 2006;Braithwaite et al, 2012). However, this conceptual diagram only provides a simplified and partial understanding of the processes involved in flocculation.…”

Section: Accepted M Manuscriptmentioning

confidence: 73%

Effective energy controls on flocculation under various wave-current regimes

et al. 2016

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Transport of sediments is a critical process in the coastal zone because of its relation with coastal erosion, productivity and pollution. Of particular interest are the dynamics of suspended cohesive sediments, known as flocs, which can aggregate and break-up during the flocculation process. This changes their size, density, settling velocity and overall transport. Even though turbulence is widely accepted to be an important control on floc aggregation and break-up, specific and detailed floc behaviour is still not fully understood. The present study seeks to help in the understanding of the intra-tidal turbulence-induced flocculation under different current-wave regimes. Observations of floc size and currents at high sample rates are used to investigate the changes throughout a fortnightly cycle. The occurrence of waves at different stages during the sampling period enabled determination of three regimes of currents dominant, combined waves and currents,

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Section: Accepted M Manuscriptmentioning

confidence: 73%

Effective energy controls on flocculation under various wave-current regimes

et al. 2016

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“…Numerous studies have been carried out in order to elucidate which of these factors-turbulence or TSM-is the more important to floc growth and settling. No general relationship between floc size and settling velocity and turbulence and TSM has been found, either in the laboratory (Krone 1962;Milligan and Hill 1998;Manning and Dyer 1999) or in the field (Berhane et al 1997;Van der Lee 1998;Hill et al 2000).…”

Section: and Dan Moffattmentioning

confidence: 99%

INSSECT—an instrumented platform for investigating floc properties close to the seabed

Mikkelsen

Milligan

Hill

et al. 2004

Limnology & Ocean Methods

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A new type of tripod, INSSECT (IN situ Size and SEttling Column Tripod), designed for floc measurements in the shallow parts of the continental shelf, is described. INSSECT orientates itself into the current so that instrumentation on it faces upstream, thereby minimizing flow disturbance. The instrumentation includes a digital floc camera, a video settling column, a unique sediment trap designed for capturing flocs intact, a laser sizer, an optical backscatterance sensor, a compass and tilt meter, and a current meter. It is designed for relatively short deployments of up to 2 weeks and can be recovered, turned around, and redeployed rapidly. It was designed for use in semi-synoptic surveys of the spatial variation in floc properties such as size and settling velocity and the factors that influence them. The paper describes the various components of the INSSECT and presents selected results from the first deployments, demonstrating its ability to turn in the current and capture single flocs intact. Contrary to recent findings on the influence on settling columns on floc size, intercomparison between the video settling column and the digital floc camera reveals that the sizes are similar.

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“…Vale la pena destacar que la parametrización (24) describe el proceso de floculación para concentraciones altas y turbulencia débil, lo que no se logra con la fórmula (2), ni con los trabajos de Trento [8] y Manning y Dyer [9]. Los intervalos empleados para la concentración y el estrés se ajustan a la descripción de áreas intermareales de la costa …”

Section: Semejanza Eulerianaunclassified

Un modelo de floculación en la suspensión

Lonin¹,

Masson

2006

Bol. Cient. CIOH

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ResumenSe presenta un modelo lagrangeano de dinámica de floculas que considera partículas minerales finas en suspensión. El modelo describe en forma discreta el movimiento turbulento de las partículas, su sedimentación dependiendo del tamaño de grano de los agregados, así como los procesos de interacción que conllevan a la agregación y disgregación de las floculas. Con base en múltiples experimentos numéricos se persigue establecer una parametrización de la floculación dependiendo de la concentración de floculas suspendidas y la energía cinética de turbulencia del fluido. Con partículas elementales de 10 pm, estrés de Reynolds de 2.34 N m"2 y concentraciones entre 1 y 550 mg l"1 se obtiene un espectro gausiano de distribución del tamaño de floculas. Aumentando el estrés, el espectro tiende a disminuir hasta que las floculas desaparecen. En adición, se logra describir en el modelo el concepto gráfico dado por Dyer sobre la floculación. En general, bajo los límites pre-establecidos del experimento, se obtiene una representación aceptable de la dinámica de floculas para las simulaciones en los modelos hidrodinámicos complejos. El uso de las parametrizaciones expuestas es sugerido en simulaciones de sedimentos cohesivos.

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A laboratory examination of floc characteristics with regard to turbulent shearing

Cited by 215 publications

References 30 publications

Effective energy controls on flocculation under various wave-current regimes

Effective energy controls on flocculation under various wave-current regimes

INSSECT—an instrumented platform for investigating floc properties close to the seabed

Un modelo de floculación en la suspensión

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