Author(s): Haoyan Dong; Henk Schuttelaars; Tom De Mulder
Linked Author(s): Tom De Mulder
Keywords: Overtide Residual dynamics Wetting and drying algorithm One-dimensional hydrodynamic model Delaware Estuary
Abstract: Nonlinear tidal processes in water motion, resulting in the generation of overtides and residual dynamics, are crucial to the morphodynamic evolution of shallow tidal systems. Traditional methodologies for explaining these processes, like that of Parker (1991), rely on perturbation methods based on the assumption of a small tidal amplitude-to-depth ratio, constraining their applicability in very shallow and intertidal areas, where this assumption is invalid. To address this limitation, we propose a new methodology based on the shallow water equations combined with Defina’s (2000) wetting and drying algorithm, which accounts for subgrid-scale topography. As a first validation step of this methodology, we applied it to a schematization of the Delaware Estuary, where very shallow or intertidal areas are absent. Forced by an M2 tidal constituent at the seaward boundary, the results are compared with Parker’s findings. Our analysis confirms the dominant role of the Nonlinear Continuity term in the M4 overtide generation, while highlighting the Elevation Effect of Friction term as a secondary contributor. For the M6 overtide, the Quadratic Velocity Friction term plays a pivotal role and aligns well with Parker's leading-order friction term. Additionally, the Elevation Effect of Friction term primarily drives the mean sea level generation. The observations above are consistent with Parker's results. In future research, the new methodology will be further explored for tidal systems with extensive intertidal areas.
Year: 2025