Numerical simulation of suspended sediment transport induced by near-shore wave breaking
Sfouni-Grigoriadou, M.T.; Kolokythas, G. K.; Dimas, A.A. (2015). Numerical simulation of suspended sediment transport induced by near-shore wave breaking, in: Mynett, A. (Ed.) 36th IAHR World Congress 2015: deltas of the future and what happens upstream. pp. 4072-4081
In: Mynett, A. (Ed.) (2015). 36th IAHR World Congress 2015: deltas of the future and what happens upstream. IAHR: [s.l.]. ISBN 9781510824348. 7509 pp., meer
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| Beschikbaar in | Auteurs |
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Documenttype: Congresbijdrage
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| Trefwoord |
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| Author keywords |
Navier-Stokes equations; wave breaking; sediment transport; bed load;suspended sediment |
| Auteurs | | Top |
- Sfouni-Grigoriadou, M.T.
- Kolokythas, G. K., meer
- Dimas, A.A.
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| Abstract |
The behavior of sediment in suspension induced by wave breaking over a constant-slope beach, is investigated. The simulations are based on the coupled numerical solution of the flow equations ( continuity and Navier-Stokes) with the transport equation for suspended sediment load. The Navier-Stokes equations subject to the fully nonlinear free-surface boundary conditions and appropriate bottom, inflow and outflow boundary conditions, while the bed concentration boundary condition for the suspended sediment, is defined by means of empirical formulas depending on the instantaneous bed shear stress. The settling velocity of sediment grains is calculated by use of an empirical formula depending on the grain diameter. The equations of fluid and sediment motion are properly transformed so that the computational domain becomes time-independent. In the present study, three cases of characteristic grain size normalized to the characteristic water depth, D-s/d = 10(-4), 2 center dot 10(-4) and 5 center dot 10(-4), are investigated. During wave breaking and also in the surf zone, strong uplift of bed sediment is observed, while the maximum height of sediment suspension reaches almost the 80% of the local depth for the case of the smallest grain size. On the contrary, sediment suspension is restricted in the vicinity of the bed, for the case of the bigger grain size. The spatial distribution of the net discharge of suspended sediment clearly indicates the tendency of sediment to move to the offshore direction. |
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