Vortex drop shafts are special manholes designed to link sewer channels at different elevations. Significant energy head dissipation occurs across these structures, mainly due to vertical shaft wall friction and turbulence in the dissipation chamber at the toe of the shaft. In the present study two aspects, sometimes neglected in the standard hydraulic design, are considered, namely the energy head dissipation efficiency and the maximum pressure force in the dissipation chamber. Different physical model results derived from the pertinent literature are analyzed. It is demonstrated that the energy head dissipation efficiency is mostly related to the flow impact and turbulence occurring in the chamber. Similarly to the drop manholes, a relation derived from a simple theoretical model is proposed for the estimation of the energy head loss coefficient. The analysis of the pressures measured on the chamber bottom allows to provide a useful equation to estimate the pressure peak in the chamber as a function of the approach flow energy head.

中文翻译：

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涡旋下降轴中的能量头耗散和流动压力

涡流落井是特殊的人孔，设计用于连接不同高度的下水道。这些结构上会产生大量的能量头耗散，这主要是由于竖井壁的垂直摩擦和轴脚趾处耗散腔中的湍流。在本研究中，考虑了两个方面，有时在标准液压设计中忽略了这两个方面，即能量头的耗散效率和耗散室内的最大压力。分析了来自相关文献的不同物理模型结果。结果表明，能量头的耗散效率主要与腔室中发生的流动冲击和湍流有关。类似于下水井，提出了一种从简单理论模型推导的关系来估算能量损失系数。