Print Email Facebook Twitter Characterization of processes involved in the reset of a subtidal bar Title Characterization of processes involved in the reset of a subtidal bar Author Blossier, B. Briere, C. Roelvink, J.A. Walstra, D.J.R. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2012-12-31 Abstract 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). Studies on reset-events from a three dimensional point of view are limited but can be found for instance in Reniers et al. (2004) and Smit (2010). This paper describes an analysis that is aimed at determining the relevant processes involved in the reset of three dimensional subtidal bars and at describing the relative influence of each of these processes. To perform this study, data collected during the ECORS campaign at Le Truc Vert (France) in 2008 are analyzed. In addition, a numerical approach is performed using a research Delft3D model forced by the Xbeach wave generator to investigate the processes involved in a reset-event. The effects of the hydrodynamic external conditions on the flow patterns in the surfzone are investigated. Then the reset is studied in details in order to understand the role of the different processes taken into account by the numerical model. The incident wave energy controls the intensity of the reset. The bar cross-shore migration is controlled by the wave breaking process. The wave breaking position and the dissipation rate of the roller energy controls the generation of Shoreward Propagating Accretionary Waves (SPAW). The straightening of the subtidal bar occurs when the conditions induce a significant longshore current in the surfzone. Subject nearshore sandbars, energetic conditions, reset, process-based modeling, bar migration, Truc Vert To reference this document use: http://resolver.tudelft.nl/uuid:7bd2e26a-9eeb-4693-9473-8978422b75c1 Publisher Coastal Engineering Research Council ISSN 2156-1028 Source ICCE 2012: Proceedings of the 33rd International Conference on Coastal Engineering, Santander, Spain, 1-6 July 2012 Part of collection Institutional Repository Document type conference paper Rights (c) 2012 The Authors Files PDF 291291.pdf 1.79 MB Close viewer /islandora/object/uuid:7bd2e26a-9eeb-4693-9473-8978422b75c1/datastream/OBJ/view