The effect of geometry and bottom friction on local bed forms in a tidal embayment

TLDR: In this paper, a 2DH idealized local morphodynamic model for a tidal channel was used to demonstrate that estuarine bars with typical length scales on the order of the tidal excursion length can develop as the result of a positive feedback between water motion, sediment transport and the sandy bottom.

About: This article is published in Continental Shelf Research.The article was published on 2002-07-01 and is currently open access. It has received 75 citations till now. The article focuses on the topics: Length scale & Suspended load.

Figures

Fig. 2. The net advective sediment fluxes entering/leaving a region D which is on one side bounded by the sidewall and on the other sides by the line h0 ¼ 0:

Fig. 8. Neutral curves for lateral modenumber n ¼ 1 for a narrow channel ðB ¼ 500 mÞ with linear friction. The solid and dashed curves refer to e ¼ 0 (inertia ignored) and e ¼ 0:07; respectively. To scale k with the width, one can multiply these values by a factor B=c ¼ 0:07:

Fig. 9. Neutral curves for lateral modenumber n ¼ 1 for a narrow channel ðB ¼ 500 mÞ with non-linear friction. The solid and dashed curves refer to e ¼ 0 (inertia ignored) and e ¼ 0:07; respectively. To scale k with the width, one can multiply these values by a factor B=c ¼ 0:07:

Table 1 Parameter values, representative for the marine part of the Western Scheldt

Fig. 3. Non-dimensional growth rate o versus non-dimensional longitudinal wavenumber k for n ¼ 1 (—), n ¼ 5 (– – –), n ¼ 20 (– –), n ¼ 100 ( ) and n ¼ 100 000 (–? –).

Table 2 Critical values of non-dimensional longitudinal wavenumber k and friction r for the first five unstable lateral mode numbers. Here B ¼ 5 km and c ¼ 7 km

Frequently asked questions

Q1. What are the contributions mentioned in the paper "The effect of geometry and bottom friction on local bed forms in a tidal embayment" ?

In the case that the width is much smaller than the tidal excursion length and non-linear bottom friction is used, there is good qualitative agreement with results from 3D models reported in literature which were applied to the same parameter regime.