Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
01 Jun 2015
Review status
This discussion paper is a preprint. It has been under review for the journal Ocean Science (OS). The revised manuscript was not accepted.
The open boundary equation
D. Diederen1, H. H. G. Savenije1, and M. Toffolon2 1Department of Water Management, Delft University of Technology, Delft, the Netherlands
2Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
Abstract. We present a new equation describing the hydrodynamics in infinitely long tidal channels (i.e., no reflection) under the influence of oceanic forcing. The proposed equation is a simple relationship between partial derivatives of water level and velocity. It is formally derived for a progressive wave in a frictionless, prismatic, tidal channel with a horizontal bed. Assessment of a large number of numerical simulations, where an open boundary condition is posed at a certain distance landward, suggests that it can also be considered accurate in the more natural case of converging estuaries with nonlinear friction and a bed slope. The equation follows from the open boundary condition and is therefore a part of the problem formulation for an infinite tidal channel. This finding provides a practical tool for evaluating tidal wave dynamics, by reconstructing the temporal variation of the velocity based on local observations of the water level, providing a fully local open boundary condition and allowing for local friction calibration.

Citation: Diederen, D., Savenije, H. H. G., and Toffolon, M.: The open boundary equation, Ocean Sci. Discuss., 12, 925-958,, 2015.
D. Diederen et al.
D. Diederen et al.


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