In the last five decades much research has been devoted to the development of predictive formulae to quantify the maximum local-scour depth developing around hydraulic structures (e.g bridge piers). Owing to the complexity of the problem, most of the proposed formulae were developed on empirical grounds, which made them susceptible to scale issues. Recently, a new theoretical approach was proposed to develop a better understanding of the physics of local scouring around piers. The analysis rested on two stringent hypotheses whereby the momentum-transport rate at the sediment–water interface was dominated by eddies belonging to the inertial range and the sediment critical bed shear stress was independent from roughness Reynolds number and relative roughness effects. The present paper builds upon that previous work and explores the scaling of the equilibrium scour depth when these two hypotheses are relaxed. Results from theoretical considerations and empirical evidence are then combined to derive a new formula for maximum local-scour depth prediction.

中文翻译：

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垂直圆柱体周围的近层涡鳞和清水局部冲刷

在过去的五年中，大量研究致力于开发预测公式，以量化围绕水工结构（例如桥墩）发展的最大局部冲刷深度。由于问题的复杂性，大多数提出的公式都是基于经验制定的，这使得它们容易受到规模问题的影响。最近，提出了一种新的理论方法，以更好地了解码头周围局部冲刷的物理学。分析基于两个严格的假设，其中沉积物 - 水界面的动量传输速率由属于惯性范围的涡流控制，沉积物临界床剪切应力与粗糙度雷诺数和相对粗糙度影响无关。本论文以之前的工作为基础，并探讨了当这两个假设放松时平衡冲刷深度的缩放。然后将理论考虑的结果和经验证据结合起来，推导出最大局部冲刷深度预测的新公式。