Print Email Facebook Twitter Advection of the salt wedge and evolution of the internal flow structure in the Rotterdam Waterway Title Advection of the salt wedge and evolution of the internal flow structure in the Rotterdam Waterway Author De Nijs, M.A.J. Pietrzak, J.D. Winterwerp, J.C. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2011-01-31 Abstract An analysis of field measurements recorded over a tidal cycle in the Rotterdam Waterway is presented. These measurements are the first to elucidate the processes influencing the along-channel current structure and the excursion of the salt wedge in this estuary. The salt wedge structure remained stable throughout the measuring period. The velocity measurements indicate decoupling effects between the layers and that bed-generated turbulence is confined below the pycnocline. The barotropic M4 overtide structure is imposed at the mouth of the estuary, and the generation of M4 overtides within the estuary is found to be relatively small. Internal tidal asymmetry does not make a significant contribution to the M4 velocity frequency band. Instead, the combination of barotropic and baroclinic forcing, in conjunction with the suppression of turbulence at the interface, provides the main explanation for the time dependence and mean structure of the flow in the Rotterdam Waterway. This gives rise to the observed differences in the length of the flood and ebb, in the magnitudes of the flood and ebb velocities, in the length of the slack water periods, and in the timing of the onset of slack water at the surface and near the bed. It results in the formation of distinct exchange flow profiles at the head of the salt wedge around slack water and the creation of maximal velocities at the pycnocline during flood. Advection governs the displacement and structure of the salt wedge since turbulent mixing is suppressed. The tidal displacement of the salt wedge controls the height of the pycnocline above the bed at a particular site. Hence, it controls the height to which bed-generated turbulence can protrude into the water column. Consequently, the authors find asymmetries in the structure of the internal flow, turbulent mixing, and bed stresses that are not related to classical internal tidal asymmetry. Subject estuariessalinitytidesCchannel flowscurrentsmixing To reference this document use: http://resolver.tudelft.nl/uuid:a542586f-c23a-46aa-893c-21fd359ccbd0 DOI https://doi.org/10.1175/2010JPO4228.1 Publisher American Meteorological Society Embargo date 2011-07-31 ISSN 1520-0485 Source http://journals.ametsoc.org/loi/phoc Source Journal of physical oceanography, 41 (1), 2011 Part of collection Institutional Repository Document type journal article Rights (c) 2011 American Meteorological Society Files PDF nijs_pietrzak_winterwerp_2011.pdf 5.53 MB Close viewer /islandora/object/uuid:a542586f-c23a-46aa-893c-21fd359ccbd0/datastream/OBJ/view