Jiang C.-B.,Changsha University of Science and Technology |
Jiang C.-B.,Key Laboratory of Water |
Chen J.,Changsha University of Science and Technology |
Chen J.,Key Laboratory of Water |
And 6 more authors.
Shuikexue Jinzhan/Advances in Water Science | Year: 2012
The devastating tsunami waves can mobilize a substantial amount of coastal sediments and considerably change the coastal morphology. Meanwhile, the study of grain size sorting on seabed is not only the core content for non-uniform sediment transport but also the key scientific issue in the study of sediment transport mechanics. A twodimensional laboratory experiment is conducted to investigate the distribution change of sediment grain sizes under the influence of waves. The initial beach slope of 1/10-1/20 is exposed to the action of N-waves. The wave free surface elevations, processes of wave uprush, back wash and run-down jump, the change of cross-shore beach profile, the initial and final distribution of sediment grain sizes are observed and measured. Results show that there is a strong down-rush following the large run-up resulted in erosion on the foreshore and deposition seaward of wave run-down. The mean grain size increases in the deposition area. The beach profiles show bar type under regular and irregular wave actions in the experiment. The mean grain size decreases in the deposition area. This experimental result is in accord with the findings of Çelikoǧlu that finer grains are winnowed from the seabed in most energetic areas by the turbulent process and then carried away to less energetic areas, resulting in coarsening of the median bed surface grain size in more energetic areas.