Morphodynamic Equilibria in Double-Inlet Systems

Morphodynamic Equilibria in Double-Inlet Systems: Existence and Stability

Deng, X. (TU Delft Mathematical Physics)
Meerman, C. (Universiteit Leiden)
Boelens, T. (Universiteit Gent)
De Mulder, T. (Universiteit Gent)
Salles, P. (Universidad Nacional Autónoma de México)
Schuttelaars, H.M. (TU Delft Mathematical Physics)

2021

The existence of morphodynamic equilibria of double-inlet systems is investigated using a cross-sectionally averaged morphodynamic model. The number of possible equilibria and their stability strongly depend on the forcing conditions and geometry considered. This is illustrated by considering a rectangular double-inlet system forced by M₂ tidal constituents only. Depending on the M₂ amplitudes and phases at both entrances, no equilibrium, one equilibrium or multiple morphodynamic equilibria may exist. In case no equilibrium is found, the minimum water depth becomes zero somewhere in the system, reducing the double-inlet system to two single-inlet systems. In the other cases, the location of the minimum water depth and the direction of the tidally-averaged sediment transport, as well as their actual values, depend strongly on the M₂ tidal characteristics. Such parameter sensitivity is also observed when including the residual and M₄ forcing contributions to the water motion, and when allowing for width variations. This suggests that, when considering a specific system, the number and stability of morphodynamic equilibria, as well as the characteristics of these quantities, can only be assessed by investigating that specific system in detail. As an example, the Marsdiep-Vlie inlet system in the Dutch Wadden Sea is considered. It is found that, by using parameter values and a geometry characteristic for this system, the water motion and bathymetry in morphodynamic equilibrium are qualitatively reproduced. Also the direction and order of magnitude of the tidally-averaged suspended sediment transport compare well with those obtained from a high-complexity numerical model.

bifurcations
double inlet systems
morphodynamic equilibria
process-based models
tidal basins

http://resolver.tudelft.nl/uuid:1015fbeb-5d11-4a71-96cb-7a49571687e1

https://doi.org/10.1029/2021JF006266

2169-9003

Journal of Geophysical Research: Earth Surface, 126 (12)

Institutional Repository

journal article

© 2021 X. Deng, C. Meerman, T. Boelens, T. De Mulder, P. Salles, H.M. Schuttelaars