T.U.E.S.Day Lecture: Mathematics
Dr. Henk Schuttelaars, staff member of the group Mathematical Physics, will give a lecture on tidal dynamics and sediment transport.
In this lecture, a mathematical model for the water motion, sediment transport and trapping in an estuary will be discussed. The water motion is modelled by the width-averaged shallow water equations, the sediment transport by an advection-diffusion equation with sources and sinks and the sediment trapping follows from requiring that the tidally averaged suspended sediment concentration does not change on the long time-scale. By using scaling analysis, asymptotic solution techniques and Fourier series to capture the temporal behavior, analytical solutions techniques can be used to obtain the vertical structure of the velocities and sediment concentrations. The horizontal patterns are obtained by employing numerical techniques.
As a case study, we consider the Ems estuary. Between 1980 and 2005, successive deepening of the Ems estuary has significantly altered the tidal and sediment dynamics. The tidal range and the surface sediment concentration has increased and the position of the turbidity zone has shifted into the freshwater zone. The model is used to determine the causes of these historical changes. From the insights gained with the model, it will be shown that an increase of estuarine length will deform the tidal characteristics so that the tidal range is decreased, and the sediment trapping in the freshwater region will decrease. These results are qualitatively reproduced by a state-of-the-art model, resulting in a new possibility to renaturalize the Ems Estuary.Register now