Zur Geometrie von Wellenrippeln in Sanden unterschiedlicher Korngröße |
| |
| Authors: | Dr Klaus-Werner Tietze |
| |
| Institution: | 1. Institut für Geologie und Pal?ontologie, Lahnberge, D-3550, Marburg
|
| |
| Abstract: | Field research of wave generated bed forms within complex sediment size distributions near the inlet of a tidal lagoon at the northern coast of Brittany has stimulated an experimental study in a laboratory wave tank. Several sediment mixtures, most of them with bimodal grain size distributions, were exposed to different monochromatic shallow water waves. The observations and measurements included the dynamics of the water waves and the generation, shape, and size of oscillatory bed forms. The experiments confirm the known relationship between grain size and ripple size. In addition it is shown that coarse sand, added to a preexisting fine bed material leads to an increasing asymmetry of ripples. There is some suggestion that the variability of ripple heights is reduced by higher contents of coarse sand. Bimodal sediment size distributions obviously do not cause unusual geometry of ripples — at least within the range of the experimental tests. The different sand size modes move together in one phase, forming structures with more or less homogeniously distributed bed material. Differentiation of sediment sorting does of course occur, but this is in the range of the whole test section. Finally the experiments allowed to test the validity of some wave formulas. The own experiments are compared with some results from field and laboratory studies of other authors. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
