Searched for: faculty%3A%22Civil%255C%252BEngineering%255C%252Band%255C%252BGeosciences%22
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Winterwerp, J.C. (author), Van Kesteren, W.G.M. (author), Van Prooijen, B.C. (author), Jacobs, W. (author)
This paper proposes a conceptual framework for erosion of cohesive sediment beds. We focus on cohesive beds, distinguishing between floc erosion, surface erosion, and mass erosion. By (our) definition, surface erosion is a drained soil mechanical process, whereas mass erosion occurs under undrained conditions. The eroding shear stress is modeled...
journal article 2012
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Te Slaa, S. (author)
Estuarine systems worldwide contain large quantities of fine (cohesive) sediment. Fate and transport of these sediments is to a large extent governed by erosion and deposition processes. Knowledge on the behaviour of these sediments is required for modeling purposes in order to predict impacts on morphology and environment as a result of e.g....
report 2012
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Jacobs, W. (author)
‘Wetlands’ in tidal lagoons and estuaries are among the most valuable ecosystems in the world. Managing these systems requires both a thorough knowledge and validated tools to predict their behavior and development. An important morpho-dynamic process herein is the erosion (‘pick-up’) of the bed, which are in inter-tidal areas often composed of...
doctoral thesis 2011
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Van Prooijen, B.C. (author), Winterwerp, J.C. (author)
The linear formulation for erosion E = M(?b??c), often applied in engineering applications, has two properties, which do not always comply with field and laboratory observations, they are as follows: (1) The erosion rate is zero below the critical bed shear stress ?c and increases linearly with bed shear stress ?b, when exceeding the critical...
journal article 2010
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Maggi, F. (author)
While the fractal dimension of suspended flocs of cohesive sediment is known to vary with the shear rate, electrochemical properties of the sediment and environment, geometrical restructuring, and presence of organic matter, experimental data presented in this work suggest changes in fractal dimension also during floc genesis at constant...
journal article 2007
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Dankers, P.J.T. (author)
Highly concentrated suspensions are present in many natural environments. When the concentration becomes large enough, particles start to interfere with each other and their settling velocity reduces. This is called hindered settling. As a result of the reduced settling velocity, particles remain in the water column for a longer time and the...
doctoral thesis 2006
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Maggi, F. (author)
Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared to transport and deposition, flocculation can...
doctoral thesis 2005
document
Maggi, F. (author)
The study of cluster format ion is common in many fields of science and technology (aerosols, colloidal suspensions, hetero-disperse particulate systems in general, growth processes far from equilibrium, etc.). The term "cluster" is a general word indicating an object consisting of a set of elementary unit es organised with a certain structure....
report 2003
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Merckelbach, L.M. (author)
Many harbours in the world suffer from high siltation rates in their basins. To guarantee safe shipping, harbour authorities have to maintain the navigable depth by having dredged large amounts of mud. Some authorities relate the navigable depth to a depth at which the density is equal to a certain value, e.g. 1200 kg/m3. However, the shear...
report 1999
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Merckelbach, L.M. (author)
Many harbours in the world suffer from high siltation rates in their basins. To guarantee safe shipping, harbour authorities have to maintain the navigable depth by dredging large amounts of mud. Some authorities relate the navigable depth to the depth at which the density is equal to a certain value, e.g. 1200 kg/m3. However, the shear strength...
report 1998
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Merckelbach, L.M. (author)
Many harbours in the world suffer from high siltation rates in their basins. To guarantee safe shipping, harbour authorities have to maintain the navigable depth by having dredged large amounts of mud. Some authorities relate the navigable depth to a depth at which the density is equal to a certain value, e.g. 1200 kg/m3. However,the shear...
report 1998
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Van der Ham, R. (author)
In 1993 an interdisciplinary research programme on the behaviour of mud in tidal waters was initiated by the The Board of NWO-BOA. The programme aims at obtaining more detailed insight in the dominant processes that govern the transport behaviour of mud. These processes have strong time variability and therefore the general approach is to obtain...
report 1996
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Van Kessel, T. (author)
In order to predict the stain and shear rate response of cohesive sediment suspensions to applied forces, their rheological properties have to be known. In this report the rheological properties of both China clay, an artificial mud, and Caland channel mud, a natural mud, are investigated. Four types of experiments are involved: equilibrium flow...
report 1996
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Van der Ham, R. (author)
Carousels have been developed in an attempt to approach the in situ hydrodynamic conditions and to obtain arealistic simulation of the erosion and deposition processes of cohesive sediments. The main advantage of a carousel over straight flumes is that effects of inflow and outflow are absent and no circulation pumps are needed which would break...
report 1996
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Merckelbach, L.M. (author)
In the framework of project Strength evolution of soft consolidating mud layers, financially supported by the Netherlands Foundation of Technology, a literature survey on consolidation theory and rheological modelling of mud was carried out. A consolidation theory, focused on the Gibson equation (Gibson et al., 1967), is presented. The solution...
report 1996
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De Wit, P.J. (author)
A research project was carried out at the Delft University of Technology in order to study the interaction between waves as weil as a current and a muddy bed. For this purpose several experiments were made on two artificial clays, namely China Clay and Westwald Clay. The results of the experiments on China Clay were reported by De Wit (1994). In...
report 1994
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De Graaff, J. (author), Slot, R.E. (author)
Recently a lot of research is being done on cohesive sediment. It plays a major role in the shoaling of harbours and waterways, and in some serious environmental problems. To predict cohesive sediment transport, information is needed about the distributions of size and settling velocities. Many methods exist to determine sizes of suspended...
report 1993
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De Wit, P.J. (author)
A research program was started to study the behaviour of cohesive sediments at the Delft University of Technology in 1989. As part of this project a well-provided physico-chemicallaboratory was built within the Hydromechanics Laboratory and adequate instrumentation was purchased. These new instruments and other instruments already present in the...
report 1992
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De Wit, P.J. (author)
In this report an overview will be given of the basic properties of (suspended) clay particles. In section 2 the structure of clay minerals will be described. The forces between suspended particles (section 3) and the possible consequences of them, flocculation or deflocculation (sections 4 and 5) will be discussed next. Section 7 will deal with...
report 1992
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