On the Mechanisms Generating the Nearshore Bars on a Sandy Coastal Slope

I. O. Leont’yev; Леонтьев И. О.

doi:10.31857/S0030157423030085

On the Mechanisms Generating the Nearshore Bars on a Sandy Coastal Slope

Authors: Leont’yev I.O.¹
Affiliations:
1. Shirshov Institute of Oceanology RAS
Issue: Vol 63, No 3 (2023)
Pages: 467-474
Section: Морская геология
URL: https://journals.rcsi.science/0030-1574/article/view/136258
DOI: https://doi.org/10.31857/S0030157423030085
EDN: https://elibrary.ru/SVBGII
ID: 136258

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Abstract
About the authors
References
Supplementary files
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Abstract

The study is aimed at investigation of the problem in what conditions the morphodynamic self-organizational mechanism controlling the growth of small perturbations arisen on bed could be responsible for the nearshore bars development. A simplified sediment transport model is used in which the sediment discharge is turned out directly proportional to the local bed slope. This model allows reducing the problem to an analytical solving of the diffusion equation which gives the base to predict the evolution of perturbation arisen on bed. The conclusion is argued that the favorable preconditions for the nearshore bar formation can exist in the case of onshore sediment transport associated with the dominating contribution of wave asymmetry in transport process. However under conditions of steep stormy waves the undertow is developed providing offshore sediment flux from the beach. In this case, the breaker bar is formed by two mechanisms–self-organization and convergence of opposite sediment fluxes. The results obtained are in agreement with available data and also assist to explain some properties of multiple-bar systems found out from observations.

Keywords

nearshore bars, multiple bar system, self-organizational mechanism, sediment transport, energy dissipation

About the authors

I. O. Leont’yev

Shirshov Institute of Oceanology RAS

Author for correspondence.
Email: igor.leontiev@gmail.com
Russia, Moscow

References

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