A Co‐Spectral Budget Model Links Turbulent Eddies to Suspended Sediment Concentration in Channel Flows
A Co‐Spectral Budget Model Links Turbulent Eddies to Suspended Sediment Concentration in Channel Flows
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DOI：
10.1029/2021wr031045
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发表时间：
2021-08
影响因子：
5.4
通讯作者：
Shuolin Li;A. Bragg;G. Katul
中科院分区：
文献类型：
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作者：
Shuolin Li;A. Bragg;G. Katul
悬浮泥沙浓度的垂向分布与水力学、水文学、生态学和水质控制等诸多问题密切相关，一直是一个研究热点。许多经典的理论发展了90年的过程中，代表了湍流对悬浮泥沙（SS）的影响，使用有效的混合长度或涡流扩散系数，而没有明确说明的能量湍流涡旋跨尺度。为了解决这一差距，沉积物的湍流通量推导使用的共谱预算（CSB）模型，可以立即用于SS和其他细颗粒物传输模型。CSB使用修改后的谱线性Rotta方案来关闭压力再分布效应，以通过修改后的尺度相关去相关时间来包括生产的各向同性以及湍流涡旋和沉积物颗粒之间的相互作用。其结果是一个公式的复杂性类似于广泛使用的劳斯方程，但所有的特征尺度，雷诺数，和施密特数的影响，来自完善的垂直速度的频谱形状和公认的常数从湍流模型。最后，所提出的CSB模型可以恢复Prandtl和Rouse方程的限制条件。
The vertical distribution of suspended sediment concentration remains a subject of active research given its relevance to a plethora of problems in hydraulics, hydrology, ecology, and water quality control. Many of the classical theories developed over the course of 90 years represent the effects of turbulence on suspended sediments (SS) using an effective mixing length or eddy diffusivity without explicitly accounting for the energetics of turbulent eddies across scales. To address this gap, the turbulent flux of sediments is derived using a co‐spectral budget (CSB) model that can be imminently used in SS and other fine particle transport models. The CSB closes the pressure‐redistribution effect using a spectral linear Rotta scheme modified to include isotropization of production and interactions between turbulent eddies and sediment grains through a modified scale‐dependent de‐correlation time. The result is a formulation similar in complexity to the widely used Rouse's equation but with all characteristic scales, Reynolds number, and Schmidt number effects derived from well‐established spectral shapes of the vertical velocity and accepted constants from turbulence models. Finally, the proposed CSB model can recover Prandtl's and Rouse's equations under restricted conditions.