This study investigates the influence of free-surface variation on the velocity field using numerical simulations of flow around a sharp-nosed pier that is representative of a typical masonry bridge pier. The study evaluates the assumption that free-surface effects are negligible at small Froude numbers by comparing the change in flow field predictions due to the use of a free-surface model (i.e. multi-phase simulation with a volume of fluid (VOF) model in place of a rigid-lid approximation (i.e. single phase simulation). Results show that simulations using the VOF model are in better agreement with experimental data than those using the rigid-lid approximation. Importantly, results show that even though the change in free-surface height near the pier is small comparative to the approach flow, it still has a significant effect on velocities in front of the pier and in the wake region, and including at low Froude numbers.

中文翻译：

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尖鼻桥墩周围流动的预测：弗劳德数和自由表面变化对流场的影响

本研究使用代表典型砌体桥墩的尖头墩周围流动的数值模拟来研究自由表面变化对速度场的影响。该研究通过比较由于使用自由表面模型（即具有流体体积 (VOF) 模型的多相模拟）导致的流场预测的变化，评估了在小 Froude 数下自由表面效应可以忽略不计的假设。代替刚盖近似（即单相模拟）。结果表明，使用 VOF 模型的模拟比使用刚盖近似的模拟更符合实验数据。重要的是，结果表明，即使自由-与引流相比，靠近码头的表面高度较小，