Relaxation time effects of wave ripples on tidal beaches
Relaxation time effects of wave ripples on tidal beaches
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DOI：
10.1029/2007gl030696
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发表时间：
2007-08
影响因子：
5.2
通讯作者：
M. Austin;G. Masselink;Tim J. O'Hare;P. Russell
中科院分区：
文献类型：
--
作者：
M. Austin;G. Masselink;Tim J. O'Hare;P. Russell
波浪波纹引起的海床粗糙度是控制近岸区泥沙输移过程的关键因素。粗糙度通常被认为是一个功能的涟漪的几何形状，这反过来，可以预测从沉积物和水动力参数。现有的涟漪预测器认为床的形态与流体动力学平衡，而最近的实验室测量表明，涟漪发展的时间尺度是几十分钟到几个小时的顺序。在这里，我们表明，潮汐海滩上的波浪波纹的显着影响的松弛时间的影响，涟漪高度和长度逐渐增加，在涨潮和保持不变，在落潮。此外，我们研究的涟漪在现有的经验模型的背景下，并建议如何在潮汐周期的时间演变可以预测。
Seabed roughness due to wave ripples is a key factor in controlling sediment transport processes in the nearshore zone. Roughness is commonly considered a function of the ripple geometry, which in turn, can be predicted from sediment and hydrodynamic parameters. Existing ripple predictors consider the bed morphology to be in equilibrium with the hydrodynamics, whereas recent laboratory measurements show that the time scale for ripple development is of the order of tens of minutes to hours. Here we show that wave ripples on tidal beaches are significantly affected by relaxation time effects, with ripple height and length progressively increasing during the rising tide and remaining constant during the falling tide. Moreover, we examine the ripples in the context of existing empirical models and suggest how the temporal evolution over a tidal cycle may be predicted.