Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-26T09:15:41.767Z Has data issue: false hasContentIssue false
  • English
  • Français

Long bed waves in tidal seas: an idealized model

Published online by Cambridge University Press:  25 September 2009

PAOLO BLONDEAUX ,
HUIB E. DE SWART  and
GIOVANNA VITTORI
PAOLO BLONDEAUX*
Affiliation:
Department of Civil, Environmental and Architectural Engineering, Genoa University, Via Montallegro 1, 16145 Genova, Italy
HUIB E. DE SWART
Affiliation:
Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
GIOVANNA VITTORI
Affiliation:
Department of Civil, Environmental and Architectural Engineering, Genoa University, Via Montallegro 1, 16145 Genova, Italy
*
†Email address for correspondence: blx@dicat.unige.it
Get access Rights & Permissions [Opens in a new window]

Abstract

An idealized model is proposed to explain the appearance of the long bed waves that have been recently observed in shallow tidal seas. The model assumes that these bedforms grow due to tide–topography interaction. The water motion is described by means of the depth-averaged shallow water equations and the bottom evolution is governed by conservation of sediment mass. The sediment transport formulation includes a critical bottom stress below which no sediment moves. Also, anisotropic sediment transport, due to local bottom slopes in the longitudinal and transverse directions, is taken into account. A linear stability analysis of the flat bottom configuration reveals that different bottom patterns can emerge. In accordance with previous analyses, for strong tidal currents, the fastest growing modes are sand banks. However, if the tidal currents are elliptical and the maximum bottom stress is just above its threshold value for the initiation of sediment motion, the model shows the presence of further growing modes which resemble the long bed waves observed in the field.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 636 , 10 October 2009 , pp. 485 - 495
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Besio, G., Blondeaux, P. & Vittori, G. 2006 On the formation of sand waves and sand banks. J. Fluid Mech. 557, 1–27.CrossRefGoogle Scholar
Carbajal, N. 1997 Two application of Taylor's problem solution for finite rectangular semi-enclosed basins. Cont. Shelf Res. 17 (7), 803–817.CrossRefGoogle Scholar
Fredsøe, J. & Deigaard, R. 1992 Mechanics of Coastal Sediment Transport. World Scientific.CrossRefGoogle Scholar
Hulscher, S. J. M. H., De Swart, H. E. & De Vriend, H. J. 1993 The generation of offshore tidal sand banks and sand waves. Cont. Shelf Res. 13, 1183–1204.CrossRefGoogle Scholar
Huthnance, J. M. 1982 On one mechanism forming linear sand banks. Est. Coast. Shelf Sci. 14, 79–99.CrossRefGoogle Scholar
Knaapen, M. A. F. 2008 Sandbank occurrence on the Dutch continental shelf in the North Sea. Geo-Mar. Lett. 29, 17–24. DOI: 10.1007/s00367-008-0105-7.CrossRefGoogle Scholar
Knaapen, M. A. F., Hulscher, S. J. M. H., De Vriend, H. J. & Stolk, A. 2001 A new type of sea bed waves. Geophys. Res. Lett. 28 (7), 1323–1326.CrossRefGoogle Scholar
Kovacs, A. & Parker, G. 1994 A new vectorial bedload formulation and its application to the time evolution of straight river channel. J. Fluid Mech. 267, 153–183.CrossRefGoogle Scholar
Meyer-Peter, E. & Muller, R. 1948 Formulas for bed-load transport. In Proceedings of the Second Meeting, International Association for Hydraulic Structures Research, Stockholm, Sweden.Google Scholar
Richards, K. J. 1980 The formation of ripples and dunes on an erodible bed. J. Fluid Mech. 99, 597–618.CrossRefGoogle Scholar
Seminara, G. 1998 Stability and morphodynamics. Meccanica 33, 59–99.CrossRefGoogle Scholar
Shapiro, G. I. 2004 A 2.5D model for sand transport in a shallow sea: effect of Ekman veering. Cont. Shelf Res. 24, 659–671.CrossRefGoogle Scholar
Soulsby, R. L. 1997 Dynamics of Marine Sands. Thomas Telford.Google Scholar
Soulsby, R. L. & Whitehouse, R. J. S. 2005 Prediction of ripple properties in shelf seas. Mark 2 predictor for time evolution. Tech. Rep. TR155 Release 2.0, HR Wallingford Ltd, UK.Google Scholar
Talmon, A. M., Struiksma, N. & Van Mierlo, M. C. L. M. 1995 Laboratory measurements of the direction of sediment transport on transverse alluvial-bed slopes. J. Hydraul. Res. 33, 495–517.CrossRefGoogle Scholar