document

Stone Stability under Stationary Nonuniform Flows

Steenstra, Remco (author), Hofland, Bas (author), Paarlberg, Andries (author), Smale, Alfons (author), Huthoff, Fredrik (author), Uijttewaal, W.S.J. (author)

A stability parameter for rock in bed protections under nonuniform stationary flow is derived. The influence of the mean flow velocity, turbulence, and mean acceleration of the flow are included explicitly in the parameter. The relatively new notion of explicitly incorporating the mean acceleration of the flow significantly improves the...

journal article 2016

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Efficiency of hanging silt curtains in cross-flow

Radermacher, M. (author), De Wit, L. (author), Uijttewaal, W.S.J. (author), Winterwerp, J.C. (author)

When dredging in sensitive environments, efforts have to be made to limit the free dispersal of suspended fine sediment from the dredging spill. Especially the use of hanging silt curtains as an environmental mitigation measure is widespread. Despite frequent application, their ability to reduce turbidity levels through vertical diversion of...

journal article 2015

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Mapping bed-level evolution in laboratory flumes by means of structured light

Angel, J.A. (author), Gorte, B.G.H. (author), Vargas Luna, A. (author), Uijttewaal, W.S.J. (author)

Experimental work in river morphology has already become a key factor to assess and analyze physical and numerical models that describe bed-level evolution in channels (Paola et al, 2009). Different techniques could be used to measure bed topography in laboratories ranging from traditional to high-technology methods. In this work, the structured...

conference paper 2014

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Validation and Optimization of a Design Formula for Stable Geometrically Open Filter Structures

Van de Sande, S.A.H. (author), Uijttewaal, W.S.J. (author), Verheij, H.J. (author)

Granular filters are used for protection against scour and erosion of base material. For a proper functioning it is necessary that at the interfaces between the filter structure, the subsoil and the water flowing above the filter structure no material will be transported. Different types of granular filters can be distinguished, this paper...

conference paper 2014

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Overtopping Flow Impact on a Vertical Wall on a Dike Crest

Chen, X. (author), Hofland, B. (author), Altomare, C. (author), Uijttewaal, J.S.W. (author)

In this paper the impact process and mechanism of overtopping flow on a vertical wall on a dike crest are investigated by means of a series of physical model tests. A double-peaked force was recognized in a time series of an overtoping flow. Four stages were summarized for the whole overtopping flow impact process. An empirical relationship...

conference paper 2014

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Image analysis for measuring the size stratification in sand-gravel laboratory experiments

Orru, C. (author), Chavarrias Borras, V. (author), Uijttewaal, W.S.J. (author), Blom, A. (author)

Measurements of spatial and temporal changes in the grain-size distribution of the bed surface and substrate are crucial to improving the modelling of sediment transport and associated grain-size selective processes. We present three complementary techniques to determine such variations in the grain-size distribution of the bed surface in sand...

journal article 2014

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Flow resistance of vegetated oblique weir-like obstacles during high water stages

Ali, S. (author), Uijttewaal, W.S.J. (author)

At high water stages, obstacles (submerged and particularly emerged vegetation) in the flood plains of a river contribute to the flow resistance and hamper the conveyance capacity. In particular the elevated vegetated parts are expected to play an important role. The objective of this research work is to determine the form drag due to vegetated...

journal article 2014

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Turbulente ondiepe stromingen

Uijttewaal, W.S.J. (author)

journal article 2014

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Meander dynamics: A reduced-order nonlinear model without curvature restrictions for flow and bed morphology

Ottevanger, W. (author), Blanckaert, K. (author), Uijttewaal, W.S.J. (author), De Vriend, H.J. (author)

Reduced-order models remain essential tools for meander modeling, especially for processes at large length scales and long time scales, probabilistic simulations, rapid assessments, or when input data are scarce or uncertain. Present reduced-order meander models consider their dependent variables either as small-amplitude variations compared to...

journal article 2013

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New laboratory techniques to determine the grain size distribution of a sandgravel bed surface and substrate (abstract)

Orru, C. (author), Eleftherakis, D. (author), Blom, A. (author), Snellen, M. (author), Uijttewaal, W.S.J. (author), Simons, D.G. (author)

Grain size changes in a river dominated by mixed sediment are the outcome of sedimentary grain sizeselective processes. Progress in the measurement techniques that define the spatial and temporal variation in grain size is necessary to provide new insights in this field. Techniques as image analysis and acoustic methods have emerged in the last...

conference paper 2013

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Effects of vegetation on sediment transport, experience from laboratory measurements (abstract)

Vargas Luna, A. (author), Uijttewaal, W.S.J. (author), Crosato, A. (author), Tanczos, I.C. (author), De Vries, M. (author)

conference paper 2013

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Flow resistance of vegetated oblique weir-like obstacles during high water stages

Ali, S. (author), Uijttewaal, W.S.J. (author)

At high water stages obstacles in the flood plains of a river contribute to the flow resistance and hamper the conveyance capacity. In particular the elevated vegetated parts are expected to play an important role. The objective of this research work is to determine the form drag due to vegetated oblique weir-like obstacles. The experiments have...

journal article 2013

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Laboratory measurements to determine the grain size distribution of the bed surface and substrate (poster)

Orru, C. (author), Blom, A. (author), Uijttewaal, W.S.J. (author)

journal article 2012

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Research on river bank accretion

Vargas Luna, A. (author), Crosato, A. (author), Uijttewaal, W.S.J. (author)

conference paper 2012

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Image analysis techniques used to determine the grain size distribution of a sand-gravel bed surface and substrate

Orru, C. (author), Blom, A. (author), Uijttewaal, W.S.J. (author)

conference paper 2012

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Hydrodynamic load on the building caused by overtopping waves

Chen, X. (author), Hassan, W. (author), Uijttewaal, W. (author), Verwaest, T. (author), Verhagen, H.J. (author), Suzuki, T. (author), Jonkman, S.N. (author)

Wide crested dike can reduce the kinetic energy of the overtopping wave and make the overtopping wave to flow back to the seaside. If a coastal town were built on or near a dike, the overtopping wave running on the dike crest generates the force which can affect the buildings located in its path. However, quantifying the hydrodynamic load on the...

conference paper 2012

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Experimental and numerical findings on the long-term evolution of migrating alternate bars in alluvial channels

Crosato, A. (author), Desta, F.B. (author), Cornelisse, J. (author), Schuurman, F. (author), Uijttewaal, W.S.J. (author)

Migrating alternate bars form in alluvial channels as a result of morphodynamic instability. Extensive literature can be found on their origin and short-term development, but their long-term evolution has been poorly studied so far. In particular, it is not clear whether migrating bars eventually reach a (dynamic) equilibrium, as in previous...

journal article 2012

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Flow resistance of vegetated oblique weir-like obstacles during high water stages

Ali, S. (author), Uijttewaal, W.S.J. (author)

At high water stages obstacles in the floodplains of a river contribute to the flow resistance. In particular the elevated vegetated parts are expected to play an important role. The objective of this study is to estimate and parameterize the form drag due to vegetated oblique weir-like obstacles. An experimental study has been carried out in...

conference paper 2011

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Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels

Crosato, A. (author), Mosselman, E. (author), Desta, F.B. (author), Uijttewaal, W.S.J. (author)

journal article 2011

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Numerical and physical modelling of rapidly varying flow over weir-like obstacles in rivers and floodplains

Ali, S. (author), Uijttewaal, W.S.J. (author)

conference paper 2011