On the mechanics of long-shore sediment transfer on the sea coasts

by

A.E. Shchodro1, D.A. Antonenkov2, A.N. Sorokin3

1Institute of Natural and Technical Systems, RF, Sevastopol, Lenin St., 28

 E-mail: ashodro@ya.ru

2Marine Hydrophysical Institute of RAS, RF, Sevastopol, Kapitanskaya St., 2

3PE «Sorokin A.N.», RF, Sevastopol

DOI: 10.33075/2220-5861-2023-4-124-134 

UDC 551.4.013                                                           

EDN: https://elibrary.ru/speyxa

Abstract:

In the mechanics of the long-shore sediment transfer on the sea coasts and reservoirs, it is necessary to consider the movement of a quasi-uniform flow disturbed by coastal waves and transfering the bulk of sediments to a suspended state when the largest waves collapse. When focusing on averagemaximum storms, it is necessary to consider the spectrum of wave energies of a given storm, and, identifying the most energetic waves occurring on the largest one out of the 20-50 regular waves, determine the amount of material being weighed based on the energy of the collapse of this wave.

A model of the wave energy spectrum for a storm of a given security is proposed and used for the quantitative analysis of sediments transferred by the long-shore flow in certain areas of the considered seashore area. A model of the movement of sediment particles during the collapse of a large wave within the coastal zone, the re-suspension of the particle mass and the beginning of their movement with a long-shore flow is also described. Further calculations aimed at determining the vertical coordinates of the beach shoal in the area of the projected structure are planned.

Such calculations are based on a system of differential equations describing convective-diffusion processes in a turbulent water flow and mass transfer conditions on the eroded bottom. The system of these equations is solved, for example, by the finite-difference method on a sufficiently condensed grid for an area representing a rectified surface formed by a smooth current line drawn in the flow diagram and vertical formations (depth verticals). Thus, the problem of bottom erosion, the particle transfer and the erosion products can be solved using the above-mentioned system of equations.

Keywords: sediment transfer, coastal protection structures, current, design, modeling, formation of beaches.

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