Transport of Fine Sands by Currents and Waves

Rijn, Leo C. van; Nieuwjaar, M.W.C.; Kaay, Theo van der; Nap, E.N.; Kampen, Arnold van

doi:10.1061/(asce)0733-950x(1993)119:2(123)

Cited by 81 publications

(37 citation statements)

References 15 publications

(14 reference statements)

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“…Complete overviews of the formulations, testing, and validation of Delft3D Online Morphology have been reported in Lesser et al (2004). See Walstra and Van Rijn (2003), and Van Rijn (1993, 2007a for the specific transport formulations. Because most fringing reefs are relatively uniform alongshore in water depth and hydrodynamic roughness at larger scales (order *100 s of m) but heterogeneous at smaller scales (order *m) due to ridge-and-runnel structures on the reef flat and spur-and-groove structures on the fore reef, a fully realistic three-dimensional model at the spatial scales necessary to resolve the heterogeneity would be too computationally intensive.…”

Section: Numerical Modelingmentioning

confidence: 99%

Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport

et al. 2011

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Most climate projections suggest that sea level may rise on the order of 0.5-1.0 m by 2100; it is not clear, however, how fluid flow and sediment dynamics on exposed fringing reefs might change in response to this rapid sea-level rise. Coupled hydrodynamic and sedimenttransport numerical modeling is consistent with recent published results that suggest that an increase in water depth on the order of 0.5-1.0 m on a 1-2 m deep exposed fringing reef flat would result in larger significant wave heights and setup, further elevating water depths on the reef flat. Larger waves would generate higher near-bed shear stresses, which, in turn, would result in an increase in both the size and the quantity of sediment that can be resuspended from the seabed or eroded from adjacent coastal plain deposits. Greater wave-and wind-driven currents would develop with increasing water depth, increasing the alongshore and offshore flux of water and sediment from the inner reef flat to the outer reef flat and fore reef where coral growth is typically greatest. Sediment residence time on the fringing reef flat was modeled to decrease exponentially with increasing sea-level rise as the magnitude of sea-level rise approached the mean water depth over the reef flat. The model results presented here suggest that a 0.5-1.0 m rise in sea level will likely increase coastal erosion, mixing and circulation, the amount of sediment resuspended, and the duration of high turbidity on exposed reef flats, resulting in decreased light availability for photosynthesis, increased sediment-induced stress on the reef ecosystem, and potentially affecting a number of other ecological processes.

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Section: Numerical Modelingmentioning

confidence: 99%

Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport

et al. 2011

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“…Figure 5-14 shows verification of some experimental cases of Zhou and Ju (2007), Havinga (1992) and van Rijn et al (1993) with low ripple steepness and Table 5-2 shows the experimental conditions. It can be seen that the calculated sediment concentration profiles fit the measured data reasonably.…”

Section: Verificationmentioning

confidence: 82%

“…As this kind of bed type is a transition zone between vortex ripples and sheet flow, the turbulence diffusion is very complex and still needs further study. Zhou and Ju (2007), Havinga (1992) and van Rijn et al (1993) …”

Section: Verificationmentioning

confidence: 99%

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Modelling and Analysis of Fine Sediment Transport in Wave-Current Bottom Boundary Layer

Zuo¹

2018

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Although all care is taken to ensure integrity and the quality of this publication and the information herein, no responsibility is assumed by the publishers, the author nor IHE Delft for any damage to the property or persons as a result of operation or use of this publication and/or the information contained herein. A pdf version of this work will be made available as Open Access via http://repository.tudelft.nl/ihe. This version is licensed under the Creative Commons To my family AbstractThe evolution and utilization of estuarine and coastal regions are greatly restricted by sediment problems. Inspired by the Caofeidian sea area in Bohai Bay, China, this study aims to better understand silty sediment transport under combined action of waves and currents, especially in the wave-current bottom boundary layer (BBL), and to improve our modelling approaches in predicting estuarine and coastal sediment transport.Field observations were carried out in northwestern Caofeidian sea area of Bohai Bay and field data were collected on several other silt-dominated coasts. Analysis shows that silt-dominated sediments are sensitive to flow dynamics: the suspended sediment concentrations (SSCs) increase rapidly under strong flow dynamics (i.e., waves or strong tidal currents which can stir up sediments), and high concentrations cause heavy sudden back siltation in navigation channels. In the following, details of silty sediment transport are studied, focusing on the BBL and high concentration layer (HCL).From laboratory experiments and theoretical analysis, an expression for sediment incipient motion is proposed for silt-sand sediment under combined wave and current conditions. The Shields number was revised by adding the cohesive force and additional static pressure, leading to an extended Shields curve.To study the HCL, a process based 1DV model was developed for flow-sediment dynamics near the bed in combined wave-current conditions. Based on the physical processes, special approaches for sediment movement were introduced, including approaches for different bed forms (rippled bed and 'flat-bed'), hindered settling, stratification effects, mobile bed effects, reference concentration and critical shear stress. The HCL was simulated and sensitivity analysis was carried out by the 1DV model on factors that impact the sediment concentration in the HCL. The results show that the HCL is affected by both flow dynamics and bed forms; the thickness of the HCL is about twice the height of the wave boundary layer; bed forms determine the shape of the concentration profile near the bottom, and flow dynamics determine the magnitude. For finer sediment, stratification effects and mobile bed effects impact the sediment concentration greatly.Finally, based on the 1DV model, the formulations of the mean sediment concentration profile of silty sediments were studied. By solving the time-averaged diffusion equation for SSC and considering the effects of bed forms, stratification and hindered settling, expressions for time-averaged SSC profile...

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“…In order to calibrate the high concentration layer near seabed, the sediment concentration profiles due to combined waves and current for multi-sized sediment simulated by the modified model are compared with the experimental values by van Rijn, et al (1993), and the results are shown in Fig. 3.…”

Section: Verificationmentioning

confidence: 99%

Simulation of Sorting Sedimentation in the Channel of Huanghua Harbor by Using 3d Multi-Sized Sediment Transport Model of Efdc

Zhang

Tan

Han

et al. 2011

Int. Conf. Coastal. Eng.

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Huanghua Harbor, located in the south-west coast of Bohai Bay, China, has frequently encountered severe channel siltation with sorting sedimentation along the channel during storm events since its construction. For prediction of channel siltation, a 3D numerical model of multi-fraction sediment transport based on the coupling of modified EFDC model and SWAN model is developed to investigate the sediment transport. It is shown from simulated results that the sorted sedimentation in the channel was well simulated in storm events, and the high sediment concentration near sea bed for silty coast during storm process can also be basically reflected by the model. Keywords: EFDC model; SWAN model; Sorting Sedimentation; multi-fraction sediment; sediment concentration INTRODUCTIONHuanghua harbor is a coal-export harbor, located at Bohai Bay, China. It is sited on a typical silty coast with very mild slope, and the medium diameter (d 50 ) on the surface layer of the beach bed is 0.0044-0.0689mm. Huanghua harbor has frequently encountered severe channel siltation during storm events since it was constructed. Extensive researches have been carried out to explore the mechanism of sediment transport and channel siltation of Huanghua Harbor. Zhang et al. (2006) and Zhao (2006) developed 2D and 3D numerical models respectively to investigate the sediment transport and channel siltation of Huanghua Harbor in storm events. Yan (2008) developed the vertical concentration profile expressions with high concentration near sea bed for silt suspension due to waves or combined waves and current.However, the properties of sorting sedimentation along the channel were not fully described in the previous models. Therefore, the objective of the present paper is to develop a numerical model to simulate the sorting sedimentation along the channel. For typical silty coasts interested here, the sediment is mainly suspended by wind waves and transported by current, so the combined wavecurrent action is very important. In shallow water, the wave breaking also plays important roles in the vertical concentration distribution of suspended sediment. In addition, the high concentration layer near the sea bed plays a significant role in the severe channel siltation. Therefore, for prediction of channel siltation of Huanghua Harbor on silty coast, a sediment transport model incorporating the above effects is needed. A 3D numerical model for multi-fraction sediment transport based on the coupling of modified EFDC model and SWAN model is developed and applied in the present paper to investigate nearshore sorting sedimentation and the channel siltation process of Huanghua Harbor under the combined action of wind, waves and current.

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Transport of Fine Sands by Currents and Waves

Cited by 81 publications

References 15 publications

Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport

Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport

Modelling and Analysis of Fine Sediment Transport in Wave-Current Bottom Boundary Layer

Simulation of Sorting Sedimentation in the Channel of Huanghua Harbor by Using 3d Multi-Sized Sediment Transport Model of Efdc

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