ABSTRACT Coastal finite structures, bridge piers, and bank protection structures may become submerged during storm surges. In the present study, a turbulent flow field around a submerged pile within a scour hole is numerically simulated considering a very fine mesh in the order of 50 million cells distributed within a relatively small computational domain. Necklace vortices, including two horseshoe vortices (HVs) and a junction vortex (JV), are detected upstream from the cylinder. In many snapshots, the tails of the HVs stretch in the flow direction, while their size and length change considerably over time. Downstream of the cylinder, the influence of the trailing vortex from the cylinder roof is mainly limited to a zone near the cylinder top, whereas the effect of the separated shear layers (SSLs) from the cylinder sides is dominant within a larger region. The strength of vorticity associated with the trailing vortex is mainly notable within the “very near wake” area, where the strength of the upward velocity component of the wake vortices generated from the cylinder sides mitigates. This paper describes the distribution and origin of streaks and rollers on the scoured bed, i.e. the main cause of sediment transported downstream of the cylinder.

中文翻译：

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当前条件下冲刷孔内沉桩周围湍流场的大涡模拟

摘要 在风暴潮期间，海岸有限结构、桥墩和护岸结构可能会被淹没。在本研究中，考虑到分布在相对较小的计算域内的 5000 万个单元的非常精细的网格，对冲刷孔内淹没桩周围的湍流场进行了数值模拟。在圆柱上游检测到项链涡流，包括两个马蹄形涡流 (HV) 和一个结涡流 (JV)。在许多快照中，HV 的尾部在流动方向上伸展，而它们的大小和长度随着时间的推移发生了很大的变化。在汽缸下游，汽缸顶尾涡的影响主要限于汽缸顶附近的区域，而从圆柱侧面分离的剪切层 (SSL) 的影响在更大的区域内占主导地位。与尾涡相关的涡流强度主要在“非常接近尾流”区域内显着，在该区域，从圆柱体侧面产生的尾流涡的向上速度分量的强度减弱。介绍了冲刷床层条痕和滚柱的分布及成因，即泥沙向筒体下游输送的主要原因。