Oblique sand ridges in confined tidal channels due to Coriolis and frictional torques     

Hepkema  Tjebbe M.  de Swart  Huib E.  Nnafie  Abdel  Schramkowski  George P.  Schuttelaars  Henk M. 《Ocean Dynamics》2020,70(12):1505-1513

Ocean Dynamics - The role of the Coriolis effect in the initial formation of bottom patterns in a tidal channel is studied by means of a linear stability analysis. The key finding is that the...  相似文献   

Sensitivity of tidal characteristics in double inlet systems to momentum dissipation on tidal flats: a perturbation analysis     

Tjebbe M. Hepkema  Huib E. de Swart  Antonios Zagaris  Matias Duran–Matute 《Ocean Dynamics》2018,68(4-5):439-455

In a tidal channel with adjacent tidal flats, along–channel momentum is dissipated on the flats during rising tides. This leads to a sink of along–channel momentum. Using a perturbative method, it is shown that the momentum sink slightly reduces the M₂ amplitude of both the sea surface elevation and current velocity and favours flood dominant tides. These changes in tidal characteristics (phase and amplitude of sea surface elevations and currents) are noticeable if widths of tidal flats are at least of the same order as the channel width, and amplitudes and gradients of along–channel velocity are large. The M₂ amplitudes are reduced because stagnant water flows from the flats into the channel, thereby slowing down the current. The M₄ amplitudes and phases change because the momentum sink acts as an advective term during the fall of the tide, such a term generates flood dominant currents. For a prototype embayment that resembles the Marsdiep–Vlie double–inlet system of the Western Wadden Sea, it is found that for both the sea surface elevation and current velocity, including the momentum sink, lead to a decrease of approximately 2% in M₂ amplitudes and an increase of approximately 25% in M₄ amplitudes. As a result, the net import of coarse sediment is increased by approximately 35%, while the transport of fine sediment is hardly influenced by the momentum sink. For the Marsdiep–Vlie system, the M₂ sea surface amplitude obtained from the idealised model is similar to that computed with a realistic three–dimensional numerical model whilst the comparison with regard to M₄ improves if momentum sink is accounted for.  相似文献