Searched for: subject:"Modelling"
(1 - 20 of 34)

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de Queiroz, Bruna (author), Scheel, F. (author), Caires, Sofia (author), Walstra, D.J.R. (author), Olij, Derrick (author), Yoo, Jeseon (author), Reniers, A.J.H.M. (author), de Boer, W.P. (author)
In process-based numerical models, reducing the amount of input parameters, known as input reduction (IR), is often required to reduce the computational effort of these models and to enable long-term, ensemble predictions. Currently, a comprehensive performance assessment of IR-methods is lacking, which hampers guidance on selecting suitable...
journal article 2019
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Huisman, B.J.A. (author), Walstra, Dirk Jan R. (author), Radermacher, Max (author), de Schipper, M.A. (author), Ruessink, B. Gerben (author)
Shoreface nourishments are commonly applied for coastal maintenance, but their behaviour is not well understood. Bathymetric data of 19 shoreface nourishments located at alongshore uniform sections of the Dutch coast were therefore analyzed and used to validate an efficient method for predicting the erosion of shoreface nourishments. Data shows...
journal article 2019
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Monecke, Katrin (author), Meilianda, Ella (author), Walstra, D.J.R. (author), Hill, Emma M. (author), McAdoo, Brian G. (author), Qiu, Qiang (author), Storms, J.E.A. (author), Masputri, Aisha Sri (author), Mayasari, Cut Deasy (author), Nasir, Muhammad (author), Riandi, Indra (author), Setiawan, Agus (author), Templeton, Caroline K. (author)
We model postseismic changes to the shoreline of West Aceh, Indonesia, a region largely affected by the December 2004 Sumatra-Andaman earthquake and ensuing Indian Ocean tsunami, using a cross-shore morphodynamic model. Subsidence of 0.5–1.0 m and tsunami scouring during the 2004 event caused the complete destruction of the beach and the...
journal article 2017
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van der Vegt, H. (author), Storms, J.E.A. (author), Walstra, D.J.R. (author), Howes, N.C. (author)
Abstract Understanding the processes and conditions at the time of deposition is key to the development of robust geological models which adequately approximate the heterogeneous delta morphology and stratigraphy they represent. We show how the mechanism of sediment transport (the proportion of the sediment supply transported as bed load vs....
journal article 2016
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Walstra, D.J.R. (author)
Nearshore sandbars have a lifetime of many years, during which they exhibit cyclic, offshore directed behaviour with strong alongshore coherence. A bar is generated near the shoreline and grows in height and width while migrating offshore, before finally decaying at the seaward limit of the surf zone. It may take 10 to 15 years for a bar to...
doctoral thesis 2016
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Walstra, D.J.R. (author), Wesselman, Daan (author), van der Deyl, Eveline (author), Ruessink, BG (author)
Inter-annual bar dynamics may vary considerably across sites with very similar environmental settings. In particular, the variability of the bar cycle return period (Tr) may differ by a factor of 3 to 4. To date, data studies are only partially successful in explaining differences in Tr, establishing at best weak correlations to local...
journal article 2016
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Reyns, J. (author), Dastgheib, A. (author), Ranasinghe, R.W.M.R.J.B. (author), Luijendijk, A.P. (author), Walstra, D.J.R. (author), Roelvink, J.A. (author)
A hampering factor in the application of morphodynamic models is the potential excessive time needed to complete a simulation. One way to upscale a model run is the use of a morphological factor, or MORFAC. In this paper, we investigate the upper limit to the value of the MORFAC as a function of model geometry and timestep for a schematized case...
conference paper 2014
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Walstra, D.J.R. (author), Ruessink, G. (author), Hoekstra, R. (author), Tonnon, P.K. (author)
Input reduction is imperative to long-term (> years) morphodynamic simulations to avoid excessive computation times. Here, we discuss the input-reduction framework for wave-dominated coastal settings introduced by Walstra et al. (2013). The framework comprised 4 steps, viz. (1) the selection of the duration of the original (full) time series of...
conference paper 2013
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Blossier, B. (author), Briere, C. (author), Roelvink, J.A. (author), Walstra, D.J.R. (author)
Sand beach profiles can exhibit nearshore sandbars with complex 3D patterns. Under energetic conditions, these patterns disappear and the bars get to a certain extent alongshore uniform. This phenomenon is called a reset. The existing literature mainly concerns the development of the bar patterns (3D) or the cross-shore migration of sandbars (2D...
conference paper 2012
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Walstra, D.J.R. (author), De Vroeg, J.H. (author), Van Thiel de Vries, J.S.M. (author), Swinkels, C. (author), Luijendijk, A.P. (author), De Boer, W.P. (author), Hoekstra, R. (author), Hoonhout, B. (author), Henrotte, J. (author), Smolders, T. (author), Dekker, F. (author), Godsey, E. (author)
In order to conceive any realistic plan for post-Katrina island restoration, it is necessary to understand the physical processes that move sand along the littoral drift zone off the coast of Mississippi. This littoral zone influences the character of the Mississippi barrier islands as they exist in an ever changing cycle. To help in this...
conference paper 2012
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Ranasinghe, R.W.M.R.J.B. (author), Swinkels, C. (author), Luijendijk, A.P. (author), Bosboom, J. (author), Roelvink, D. (author), Stive, M.J.F. (author), Walstra, D.J.R. (author)
The Morphological Acceleration Factor (MORFAC) approach for morphodynamic upscaling enables the simulation of long term coastal evolution. However the general validity of the MORFAC concept for coastal applications has not yet been comprehensively investigated. Furthermore, a robust and objective method for the a priori determination of the...
conference paper 2010
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Luijendijk, A. (author), Henrotte, J. (author), Walstra, D.J.R. (author), van Ormondt, M. (author)
A quasi-three-dimensional model (quasi-3D) has been developed through the implementation of an analytical 1DV flow model in existing depth-averaged shallow water equations. The model includes the effects of waves and wind on the vertical distribution of the horizontal velocities. Comparisons with data from both physical and field cases show that...
conference paper 2010
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Geleynse, N. (author), Storms, J.E.A. (author), Stive, M.J.F. (author), Jagers, H.R.A. (author), Walstra, D.J.R. (author)
Present?day observations and classical classification schemes of alluvial deltas address feeder channel dynamics and multiple sediment fractions. However, high?resolution physics?based mathematical models have not been applied to address formation of both fluvio?deltaic links (channels) and nodes (diffluences and confluences), and their...
journal article 2010
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Walstra, D.J.R. (author)
report 2008
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Ruessink, B.G. (author), Kuriyama, Y. (author), Reniers, A.J.H.M. (author), Roelvink, J.A. (author), Walstra, D.J.R. (author)
We compare predictions of a coupled, wave-averaged, cross-shore waves-currents-bathymetric evolution model to observations of onshore and offshore nearshore sandbar migration. The observations span a 10- and 44-day period with onshore/offshore bar migration at Duck, North Carolina, and at Hasaki, Kashima Coast, Japan, respectively, a 3.5-month...
journal article 2007
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Walstra, D.J.R. (author), Koster, L. (author)
report 2006
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Walstra, D.J.R. (author), Ormondt, M. van (author), Roelvink, J.A. (author)
report 2004
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Rijn, L.C. van (author), Walstra, D.J.R. (author), Ormondt, M. van. (author)
report 2004
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Rijn, L.C. van (author), Walstra, D.J.R. (author)
report 2004
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Rijn, L.C. van (author), Walstra, D.J.R. (author)
report 2004
Searched for: subject:"Modelling"
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