Modeling large scale shoreline sand waves under oblique wave incidence
Modeling large scale shoreline sand waves under oblique wave incidence
复制标题
斜波入射下大规模海岸线沙波建模
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
F. Ribas
中科院分区：
文献类型：
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作者：
N. V. D. Berg;A. Falqués;F. Ribas
波浪的波长在2到5公里之间，它们以大约0.5公里/年的速度向下漂移，在13年内达到120米的振幅。较大的波浪起伏度、较高的波浪高度和较短的波浪周期会加强海岸线的不稳定性。越岸输运对沙波的不稳定性至关重要，越岸动力学的加快导致沙波的快速增长。不同入射角（60 °和30 °交替）的模拟结果表明，自发沙波的形成需要很大比例的高角度波（至少80%）。深入了解背后的物理机制高角度波不稳定性和发生的最佳长度尺度沙波增长。通用模型的结果与现有的海岸线沙波观测，特别是与那些沿着非洲西南海岸是一致的。
waves develop with wavelengths between 2 and 5 km, they migrate downdrift at about 0.5 km/yr and they reach amplitudes up to 120 m within 13 years. Larger wave obliquity, higher waves and shorter wave periods strengthen the shoreline instability. Cross-shore transport is essential for the instability and faster cross-shore dynamics leads to a faster growth of the sand waves. Simulations with variable wave incidence angles (alternating between 60 � and 30 � ) show that a large proportion of high angle waves is required for spontaneous sand wave formation (at least 80%). Insight is provided into the physical mechanism behind high angle wave instability and the occurrence of a optimal length scale for sand wave growth. The generic model results are consistent with existing observations of shoreline sand waves, in particular with those along the southwest coast of Africa.