Linear evolution of sandwave packets

Share/Save/Bookmark

Roos, P.C. and Blondeaux, P. and Hulscher, S.J.M.H. and Vittori, G. (2005) Linear evolution of sandwave packets. Journal of geophysical research. Pt. F: Earth surface, 110 (F4). F04S14. ISSN 0148-0227

[img]
Preview
PDF
617Kb
Abstract:We investigate how a local topographic disturbance of a flat seabed may become morphodynamically active, according to the linear instability mechanism which gives rise to sandwave formation. The seabed evolution follows from a Fourier integral, which can generally not be evaluated in closed form. As numerical integration is rather cumbersome and not transparent, we propose an analytical way to approximate the solution. This method, using properties of the fastest growing mode only, turns out to be quick, insightful, and to perform well. It shows how a local disturbance develops gradually into a sandwave packet, the area of which increases roughly linearly with time. The elevation at the packet¿s center ultimately tends to increase, but this may be preceded by an initial stage of decrease, depending on the spatial extent of the initial disturbance. In the case of tidal asymmetry, the individual sandwaves in the packet migrate at the migration speed of the fastest growing mode, whereas the envelope moves at the group speed. Finally, we apply the theory to trenches and pits and show where results differ from an earlier study in which sandwave dynamics have been ignored.
Item Type:Article
Copyright:© 2005 American Geophysical Union
Faculty:
Engineering Technology (CTW)
Research Group:
Link to this item:http://purl.utwente.nl/publications/48934
Official URL:http://dx.doi.org/10.1029/2004JF000196
Export this item as:BibTeX
EndNote
HTML Citation
Reference Manager

 

Repository Staff Only: item control page

Metis ID: 220754