Equilibrium and stability of a double inlet system

Master thesis (2006)

Authors

R.L. Brouwer

Contributors

M.J.F. Stive (mentor)

J. van de Kreeke (mentor)

T.J. Zitman (mentor)

H.M. Schuttelaars (mentor)

Z.B. Wang (mentor)

Faculty

Civil Engineering and Geosciences () (TU Delft)

Borsje North Sea Hydrodynamics CT05.20 Delft Cluster Tidal inlets Noordzee & kust CT05.24.11 Morfodynamiek van Noordzee en kust en kustverdediging Barrier island coasts Wadden coast Double inlet system Flow diagram Van de Kreeke

To reference this document use:

http://resolver.tudelft.nl/uuid:ae0d95bd-2958-4efd-9a5d-22fd97d7d7ee

More Info

expand_more

Published Date

2006-05

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Faculty

Civil Engineering and Geosciences

Abstract

Barrier island coasts are a common feature in many parts of the world. An example is the Wadden coast of The Netherlands, Germany and Denmark. These coasts consist of barrier islands separated by tidal inlets with at the landward side tidal basins.Characteristic for the Wadden Sea is that the tidal basins are not completely separated,but are connected via topographic highs allowing exchange of water between the basins. As a result the tidal inlets that connect the basins to the North Sea will interact. The focus in this thesis is on the effect of this interaction on the cross-sectional equilibrium and stability of tidal inlets that are part of a double inlet system. The knowledge gained in this study will help to develop rational management plans for this kind of system. In determining the equilibrium values and stability of cross-sectional areas of the inlets use is made of flow diagrams. A flow diagram consists of the equilibrium flow curves of each inlet and a flow field showing the adaptation of the inlet cross-sections after the system has been removed from equilibrium. Each intersection of the equilibrium flow curves represents a stable or unstable equilibrium. The equilibrium flow curve for each inlet is the locus of the values of the cross-sectional areas for which the velocity amplitude in the inlet equals the equilibrium velocity i.e. approximately 1 m/s according to ESCOFFIER [1940]. As a start the double inlet system is schematized as a basin connected to the ocean by two channels. The water surface area of the basin is assumed constant and water levels are assumed to fluctuate uniformly. On the seaward side a simple harmonic, semidiurnal tide is used to force the system. Analyzing the double inlet system under these conditions by means of the flow diagrams leads to the conclusion that a stable equilibrium of the two inlets does not exist. Ultimately only one inlet remains open and the other will close. This confirms the earlier conclusions of VAN DE KREEKE [1990] and BORSJE [2003] concerning the cross-sectional stability of multiple inlet systems.

Files

2006Brouwer.pdf

(pdf | 2.4 Mb)

Unknown license