- document
-
Van Prooijen, B.C. (author), Uijttewaal, W.S.J. (author)The development of large coherent structures in a shallow mixing layer is analyzed. The results are validated with experimental data obtained from particle tracking velocimetry. The mean flow field is modeled using the self-similarity of the velocity profiles. The characteristic features of the down-stream development of a shallow mixing layer...journal article 2002
- document
-
Van Prooijen, B.C. (author), Uijttewaal, W.S.J. (author)This study demonstrates the importance of a sophisticated sub-grid model when performing a depth-averaged unsteady RANS simulation of a shallow flow. The reduction of resolution and the spatial dimensions exclude important physical processes as present in three-dimensional turbulence. Especially the effect of the bottom turbulence on the...journal article 2008
- document
-
Van Balen, W. (author), Uijttewaal, W.S.J. (author), Blanckaert, K. (author)After validation with experimental data, large-eddy simulation (LES) is used to study in detail the open-channel flow through a curved flume. Based on the LES results, the present paper addresses four issues. Firstly, features of the complex bicellular pattern of the secondary flow, occurring in curved open-channel flows, and its origin are...journal article 2009
- document
-
Van Balen, W. (author), Uijttewaal, W.S.J. (author), Blanckaert, K. (author)Large-eddy simulation (LES) is performed of a curved open-channel flow over topography based on the laboratory experiment by Blanckaert [“Topographic steering, flow circulation, velocity redistribution and bed topography in sharp meander bends,” Water Resour. Res., doi:10.1029/2009WR008303 (in press)] . In the experiment, the large-scale bed...journal article 2010
- document
-
Sukhodolov, A.N. (author), Schnauder, I. (author), Uijttewaal, W.S.J. (author)Shallow lateral shear layers forming between flows with different velocities, though essential for mixing processes in natural streams, have been examined only in laboratory settings using smooth, fixed?bed channels. This paper reports the results of an experimental study of a shear layer in a straight reach of a natural river where the layer,...journal article 2010
- document
-
Vermaas, D.A. (author), Uijttewaal, W.S.J. (author), Hoitink, A.J.F. (author)Research on lateral exchange of streamwise momentum between parallel flows in open channels has mainly been focused on compound channels composed of a main channel and a floodplain, on mixing layer development downstream of river confluences, and on partially vegetated channels. This study aims to establish the mechanisms responsible for...journal article 2011
- document
-
Crosato, A. (author), Mosselman, E. (author), Desta, F.B. (author), Uijttewaal, W.S.J. (author)Alternate bars in straight alluvial channels are migrating or nonmigrating. The currently accepted view is that they are nonmigrating if the width-to-depth ratio is at the value of resonance or if the bars are forced by a persistent local perturbation. We carried out 2-D numerical computations and a long-duration mobile-bed flume experiment to...journal article 2011
- document
- Crosato, A. (author), Mosselman, E. (author), Desta, F.B. (author), Uijttewaal, W.S.J. (author) journal article 2011
- document
-
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
- document
- Orru, C. (author), Blom, A. (author), Uijttewaal, W.S.J. (author) journal article 2012
- document
-
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
- document
-
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
- document
- Uijttewaal, W.S.J. (author) journal article 2014
- document
-
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
- document
-
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
- document
-
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
- document
-
Vargas Luna, A. (author), Crosato, A. (author), Calvani, G. (author), Uijttewaal, W.S.J. (author)Simulating the morphological adaptation of water systems often requires including the effects of plants on water and sediment dynamics. Physical and numerical models need representing vegetation in a schematic easily-quantifiable way despite the variety of sizes, shapes and flexibility of real plants. Common approaches represent plants as rigid...journal article 2016
- document
-
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
- document
-
Orru, C. (author), Blom, A. (author), Uijttewaal, W.S.J. (author)Armor breakup and reformation was studied in a laboratory experiment using a trimodal mixture composed of a 1mm sand fraction and two gravel fractions (6 and 10mm). The initial bed was characterized by a stepwise downstream fining pattern (trimodal reach) and a downstream sand reach, and the experiment was conducted under conditions without...journal article 2016
- document
-
Maljaars, J.M. (author), Labeur, R.J. (author), Möller, M. (author), Uijttewaal, W.S.J. (author)In this work the feasibility of a numerical wave tank using a hybrid particle-mesh method is investigated. Based on the Fluid Implicit Particle Method (FLIP) a generic formulation for the hybrid method is presented for incompressible multi-phase flows involving large density jumps and wave generating boundaries. The performance of the method...journal article 2017