Print Email Facebook Twitter The importance of time-varying, non-tidal currents in modelling in-situ sand wave dynamics Title The importance of time-varying, non-tidal currents in modelling in-situ sand wave dynamics Author Overes, P.H.P. (TU Delft Applied Mechanics; University of Twente) Borsje, B. W. (University of Twente) Luijendijk, Arjen (TU Delft Coastal Engineering) Hulscher, S. J.M.H. (University of Twente) Date 2024 Abstract Sand waves are found on shallow, sandy seabeds throughout the world and their dynamics may pose an imminent threat to offshore construction. Therefore, there is a pressing need to understand bed level dynamics in sand wave areas. These bed level dynamics lead to variations in sand wave shape and migration rate over time. However, these variations cannot be explained with the present-day process-based sand wave models, which all include a purely periodic tidal forcing. To explain these fluctuations a more intricate description of the hydrodynamics is necessary. The aim of this study is to explore the importance of time-varying, non-tidal currents for sand wave dynamics in the North Sea. We adopted the three-dimensional Delft3D-Flexible Mesh model, and were able to reconstruct time-varying, non-tidal currents on top of the periodic tidal forcing, while significantly reducing computation times. The simulated currents and water levels showed a good agreement with in-situ measurements. Compared to the situation with only tidal forcing, the simulated sedimentation and erosion rates were amplified up to 15 times due to time-varying, non-tidal currents. Additionally, periods of net erosion were found at locations in the sand wave transect where tidally forced models only showed net-sedimentation. It is therefore important to consider time-varying, non-tidal currents when predicting future sand wave dynamics in the field. Subject ADCP field measurementsDelft3D Flexible MeshHydrodynamic modellingMarine dunesSediment transport modellingTidal sand waves To reference this document use: http://resolver.tudelft.nl/uuid:361ebc5f-5249-43e0-a8a5-ae38cddbec68 DOI https://doi.org/10.1016/j.coastaleng.2024.104480 ISSN 0378-3839 Source Coastal Engineering, 189 Part of collection Institutional Repository Document type journal article Rights © 2024 P.H.P. Overes, B. W. Borsje, Arjen Luijendijk, S. J.M.H. Hulscher Files PDF 1-s2.0-S0378383924000280-main.pdf 4.19 MB Close viewer /islandora/object/uuid:361ebc5f-5249-43e0-a8a5-ae38cddbec68/datastream/OBJ/view