ABSTRACT

A major drainage systemwhich uses urban roadways as flood passages during extreme storm events has been proven to be effective and low-cost. However, to date, the amount of flow diverted at a bifurcating road crossing still could not be accurately assessed. Previous studies mainly focused on diversion flat bottom channels with no turning radius. Results from these studies are not applicable to the road crossing due to the significant discrepancies between the two flow fields. In this study, the flow distribution pattern at a roadway crossing with a T-shape was studied experimentally and numerically. The three-dimensional computational fluid dynamics (CFD) model was constructed using FLUENT. The numerical model was validated using the experimental results and showed satisfying agreements. Results of the 2^k factorial design experiments show that the flow distribution ratio is sensitive to turning radius, longitude slope, flowrate and downstream boundary conditions. Detailed numerical studies were conducted to reveal the relationship between the flow distribution ratio and the individual impacting factor. Findings from this research could provide more accurate flowrate predictions to guide the design of the road crossings to improve the performance of the major drainage system during extreme storms.

摘要

在极端风暴事件期间使用城市道路作为洪水通道的主要排水系统已被证明是有效且低成本的。然而，迄今为止，仍无法准确评估分叉路口分流的流量。以往的研究主要集中在无转弯半径的导流平底渠道。由于两个流场之间的显着差异，这些研究的结果不适用于道路交叉口。在这项研究中，通过实验和数值研究了 T 形道路交叉口处的流量分布模式。三维计算流体动力学 (CFD) 模型是使用 FLUENT 构建的。使用实验结果验证了数值模型，并显示出令人满意的一致性。^2k的结果因子设计实验表明，流量分配比对转弯半径、经度坡度、流量和下游边界条件敏感。进行了详细的数值研究以揭示流量分配比与个体影响因素之间的关系。这项研究的结果可以提供更准确的流量预测，以指导道路交叉口的设计，以改善极端风暴期间主要排水系统的性能。