A simple model for vertical profiles of velocity and suspended sediment concentration in straight and curved submarine channels
A simple model for vertical profiles of velocity and suspended sediment concentration in straight and curved submarine channels
复制标题
直线和弯曲海底通道中速度和悬浮泥沙浓度垂直剖面的简单模型
DOI：
10.1002/2013jf002812
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
J. Imran
中科院分区：
文献类型：
--
作者：
M. Bolla Pittaluga;J. Imran
建立了一个简单的模型来描述海底航道中流速和悬沙浓度的垂向分布。本文考虑定常均匀流条件下封闭河道中的保守浊流。密度分层的湍流闭合是根据梅洛尔和山田（1982）的模型修改的。直和常曲率通道的解决方案。在后一种情况下，为了评估由曲率引起的二次流，我们利用了这样一个事实，即流深曲率半径的比率通常是小的领域，这导致通过适当的渐近展开的控制方程的解决方案。在直通道纵向流速剖面与实验和现场观测结果的比较表明，一个很好的协议，并允许从已知的床坡度，当前的厚度，并在浊流-环境水界面的归一化速度的浓度分布和悬浮泥沙的大小进行预测。该模型能够捕获垂直方向上存在的多个循环单元以及近底二次流的旋转方向，相对于经典河流方向，该旋转方向可以是反向（向外）或正常方向（向内）。确定了控制海底通道二次流方向的参数，并讨论了这些参数对河床形态的影响。本文还讨论了这种方法的潜在用途和未来发展。
We develop a simple model to describe vertical profiles of velocity and suspended sediment concentration in submarine channels. We consider a conservative turbidity current flowing in a confined channel under steady and uniform flow conditions. The turbulence closure for density stratification is adapted from the model of Mellor and Yamada (1982). Solutions are obtained for both straight and constant curvature channels. In the latter case, in order to evaluate the secondary flow induced by curvature, we take advantage of the fact that the ratio of flow depth to radius of curvature is typically small in the field, which leads to a solution of the governing equations through an appropriate asymptotic expansion. Comparison of results on longitudinal velocity profiles in straight channels with experimental and field observations shows an excellent agreement and allows for the prediction of concentration profiles and suspended sediment size from known bed slope, current thickness, and normalized velocity at the turbidity current‐ambient water interface. The model is able to capture the presence of multiple circulation cells on the vertical and the sense of rotation of the near‐bottom secondary flow that can be either reversed (directed outward) or normal oriented (directed inward) with respect to the classical fluvial orientation. The parameters controlling the orientation of secondary flow in submarine channels are identified, and the implications on the bed morphology are discussed. The potential use and future developments of the present approach are also discussed.