An experimental campaign on long-term clear-water scour at bridge piers with different configurations was performed in a laboratory to investigate the effects of different countermeasures. Tests were performed in a flume with a movable sediment bed for an unprotected cylindrical pier, a cylindrical pier with a standard collar and a cylindrical pier with a bordered collar. The scoured beds at the equilibrium stage were acquired through the photogrammetry technique and the efficiencies of the tested countermeasures were measured. Results showed a reduction in the maximum scour depth as well as in the scour hole volume with respect to the unprotected pier. The maximum scour depth was reduced by 59.63% with the standard collar and by 63.51% with the bordered collar. The scoured volume was reduced by 43.80% with the standard collar and by 60.00% with the bordered collar. The three-dimensional Reynolds-averaged Navier–Stokes equations were solved numerically to reproduce the hydrodynamics of the experiments. The volume of fluid technique was used to reproduce the free surface. For each test, the results of the simulations were analysed to investigate the flow field around the pier both at the initial (flat-bed) and at the equilibrium stages, highlighting the changes in the velocity field owing to the presence of the standard collar and of the bordered collar.

中文翻译：

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有边领的流体动力学作为防止码头冲刷的对策

在实验室进行了不同配置桥墩的长期清水冲刷实验，以研究不同对策的效果。测试是在一个带有可移动沉积床的水槽中进行的，用于无保护的圆柱形桥墩、带有标准接箍的圆柱形桥墩和带有边框接箍的圆柱形桥墩。通过摄影测量技术获得了平衡阶段的冲刷床，并测量了测试对策的效率。结果表明，相对于未受保护的桥墩，最大冲刷深度和冲刷孔体积均有所减少。标准衣领的最大冲刷深度减少了 59.63%，边缘衣领减少了 63.51%。标准项圈的冲刷量减少了 43.80%，减少了 60%。00% 带镶边衣领。三维雷诺平均 Navier-Stokes 方程被数值求解以重现实验的流体动力学。流体体积技术用于再现自由表面。对于每个测试，分析模拟结果以研究初始（平床）和平衡阶段桥墩周围的流场，突出显示由于标准环的存在而导致的速度场变化和镶边的衣领。