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Bosboom, J. (author), Reniers, A.J.H.M. (author)The accuracy of morphological predictions is generally measured by an overall point-wise metric, such as the mean-squared difference between pairs of predicted and observed bed levels. Unfortunately, point-wise accuracy metrics tend to favour featureless predictions over predictions whose features are (slightly) misplaced. From the perspective...journal article 2014
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Reniers, G.L.L.M.E. (author), Brijs, T. (author)The safety-related economic (cost-benefit and cost-effectiveness) tools and models discussed in this paper allow the user to execute an investment analysis, in order to evaluate investments in preventive measures related to occupational accidents. The available software shows that there are a multitude of indirect consequences of occupational...journal article 2014
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Reniers, G.L.L.M.E. (author)The paper argues that organisations who invest intelligently in safety and security, regardless the macroeconomic situation, will have a competitive advantage over their competitors not doing so. Establishing and maintaining a competitive advantage is all about excellence. Excellent results actually require seven domains to be focussed upon: ...journal article 2014
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De Schipper, M.A. (author), De Vries, S. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A. (author), Stive, M.J.F. (author)The present paper examines the generation and inter-annual evolution of alongshore variability in topography measured after the implementation of a sand nourishment. The magnitude of the topographic variability is quantified using 3.5 years of monthly survey data. The emergence and temporal change in alongshore morphological variability is...conference paper 2013
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Bosboom, J. (author), Reniers, A.J.H.M. (author)The quality of a morphological prediction is often expressed by an overall grid-point based skill score based on the Mean Squared Error (MSE) between the predicted and observed bed levels (Sutherland et al., 2004). Although the MSE is a good measure of the overall error between model and observations, it tends to penalize rather than reward the...conference paper 2013
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Reniers, A.J.H.M. (author), Gallagher, E.L. (author), MacMahan, J.H. (author), Brown, J.A. (author), Van Rooijen, A.A. (author), Van Thiel de Vries, J.S.M. (author), Van Prooijen, B.C. (author)Novel observations of surface grain-size distributions are used in combination with intra-wave modeling to examine the processes responsible for the sorting of sediment grains on a relatively steep beach (slope?=?1:7.5). The field observations of the mean grain size collected with a digital camera system at consecutive low and high tides for a 2...journal article 2013
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De Schipper, M.A. (author), De Vries, S. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A.J.H.M. (author), Stive, M.J.F. (author)Typically a beach is out of equilibrium after a nourishment is installed. To observe how a nourished beach behaves on the timescale of storms a monitoring campaign was set up at Vlugtenburg beach after a nourishment in the spring of 2009. Here we show a sediment budget analysis of the first 2.5 years for a coastal domain spanning 1750 m...conference paper 2012
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Van Rooijen, A. (author), Reniers, A. (author), Van Thiel de Vries, J.S.M. (author), Blenkinsopp, C. (author), McCall, R. (author)A one-dimensional hydrostatic version of the XBeach model (Roelvink et al., 2009) is applied to hindcast swash morphodynamics measured during an accretive, and an erosive tide at Le Truc Vert beach (France) in early spring 2008 (Masselink et. al, 2009; Blenkinsopp et al., 2011). Swash hydrodynamics are solved by applying the nonlinear shallow...conference paper 2012
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De Schipper, M.A. (author), Reniers, A. (author), MacMahan, J. (author), Ranasinghe, R.W.M.R.J.B. (author)Field observations and numerical model simulations are examined to investigate the magnitude of vortical very low frequency (VLF) velocity fluctuations (i.e. large scale surfzone eddies) under different offshore wave forcing. Observations of vortical VLF motions under shore -normal wave incidence at Duck, NC, USA are re-analyzed and compared...conference paper 2012
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Henriquez, M. (author), Reniers, A.J.H.M. (author), Ruessink, B.G. (author), Stive, M.J.F. (author)The cause of sediment suspension events during flow reversal under waves in the nearshore is not well understood. Vortex tubes and horizontal pressure gradients have been suggested to be the cause of the suspension events. A medium sized wave flume experiment has been conducted to give insight in the hydrodynamics of the wave bottom boundary...conference paper 2012
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Senechal, N. (author), Abadie, S. (author), Gallagher, E. (author), MacMahan, J. (author), Masselink, G. (author), Michallet, H. (author), Reniers, A. (author), Ruessink, G. (author), Russell, P. (author), Sous, D. (author)A large multi-institutional nearshore field experiment was conducted at Truc Vert, on the Atlantic coast of France in early 2008. Truc Vert’08 was designed to measure beach change on a long, sandy stretch of coast without engineering works with emphasis on large winter waves (offshore significant wave height up to 8 m), a three-dimensional...journal article 2011
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Van Thiel de Vries, J.S.M. (author), Van Dongeren, A.R. (author), McCall, R. (author), Reniers, A. (author)The effect of the longshore dimension on dune erosion is examined numerically with a 2DH process based model XBeach. Exploratory simulations are presented to examine longshore effects due to directionally spread waves, longshore variation in topography and longshore variation in bathymetry. The simulations reveal that alongshore sediment...conference paper 2011
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De Schipper, M.A. (author), Ranasinghe, R.W.M.R.J.B. (author), Reniers, A.J.H.M. (author), Stive, M.J.F. (author)Nearshore rhythmicity is often initiated in the period just after a storm where the subtidal bar is turned alongshore uniform. The initiation time as well as the length scales of the created rhythmicity varies from one storm period to another. Here we show that the post-storm wave conditions are related to the initiation of the morphological...conference paper 2010
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Smit, M. (author), Reniers, A. (author), Stive, M.J.F. (author)Nearshore sandbars appear with various patterns which may change over time. From observations, these changes seem to be related to changes in hydrodynamic conditions, although observed length scales could not be related directly to occurring wave conditions. The current work investigated the role of both the concurrent and previous hydrodynamics...conference paper 2010
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Henriquez, M. (author), Reniers, A. (author), Ruessink, G. (author), Stive, M.J.F. (author)To study onshore bar migration and the accompanying intra-wave sediment transport a wave flume experiment was conducted. The wave flume had a rigid bottom with a single bar profile. The focus of the experiment was to measure the hydrodynamics in the wave bottom boundary layer. The results show that the skewness of bottom stress is not only...conference paper 2010
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MacMahan, J.H. (author), Reniers, A.J.H.M. (author), Thornton, E.B. (author)Observations of velocity fluctuations with periods between about 4 and 30 min, thus longer than infragravity waves and referred to as very low frequency (VLF) surf zone motions, are described and compared with numerical simulations. The VLF motions discussed here exclude instabilities (generated by the wave-driven alongshore current velocity...journal article 2010
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Reniers, A.J.H.M. (author), MacMahan, J.H. (author), Beron-Vera, F.J. (author), Olascoaga, M.J. (author)The trapping and ejection of surfzone floating material is examined by unveiling Lagrangian Coherent Structures (LCSs) hidden in the pulsating rip?current surface velocity field produced by a three?dimensional numerical model resolving wave?group induced Very Low Frequency motions (VLFs). LCSs explain the typically observed patchiness of flotsam...journal article 2010
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Brown, J. (author), MacMahan, J. (author), Reniers, A.J.H.M. (author), Thornton, E. (author)Absolute and relative diffusivity are measured on a rip-channeled beach using 30 position-tracking drifters released in clusters (4–12 drifters) deployed on 7 days with different wave forcing and tidal elevations at Sand City, Monterey Bay, California. Diffusivity and dispersion were found to be larger on days with rip current flow patterns and...journal article 2009
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Reniers, A.J.H.M. (author), MacMahan, J.H. (author), Thornton, E.B. (author), Stanton, T.P. (author), Henriquez, M. (author), Brown, J.W. (author), Brown, J.A. (author), Gallagher, E. (author)The retention of floating matter within the surf zone on a rip-channeled beach is examined with a combination of detailed field observations obtained during the Rip Current Experiment and a three-dimensional (3-D) wave and flow model. The acoustic Doppler current profiler–observed hourly vertical cross-shore velocity structure variability over a...journal article 2009
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De Schipper, M.A. (author), De Vries, S. (author), Henriquez, M. (author), Reniers, A.J.H.M. (author), De Koning Gans, H.J. (author), Labeur, R.J. (author), Stive, M.J.F. (author)In this paper a new wave pool concept is presented using ship hulls as wave generators. To evaluate the potential of such a concept a towing tank experiment is conducted to investigate ship wave generation in a confined space. In the towing tank experiment various hull sizes and velocities are examined to maximize the generated wave height. The...conference paper 2009