城市街道分水口对洪水流态转换过程影响研究

随着城市化进程加快和全球气候变化加剧，城市洪涝灾害频发。研究城市街道的行洪特征，掌握城市建筑物对洪水流动的影响机理，对城市洪涝灾害治理具有重要的理论意义和应用价值。本文开展了城市建筑物对洪水运动影响的物理模型试验，在街道两侧布设分水口模拟建筑物不连续的分流效果，分析分水口位置及流量变化对洪水流态转化及水跃形态的影响。观测上游来流量变化、分水口位置等因素对洪水从急流向缓流过渡时的动力特征的影响，包括水跃发生位置、水跃形态转变、水跃漩滚长度、跃前和跃后水深比及分流比等。

Effects of diverting flow on urban streets on flow pattern transition

With accelerating urbanization and aggravating global climate changes, urban flood disasters occur frequently. It is theoretically and practically of great significance to study the characteristics of flood discharging on urban streets and grasp the mechanism of how it is influenced by urban buildings. This study has conducted a series of physical model tests focusing on the influence of urban buildings on flood water movement, arranging water outlets on both sides of the main street to simulate lateral flow diversion between the buildings of discontinuous distribution. For the main street flood flow, the influence of the outlet locations on its pattern transition is analyzed; a detailed observation and analysis are made on the dynamics of the transition from supercritical to subcritical flow and its responses to changes in upstream inflow and diverting outlet locations. We find the parameters of the hydraulic jump－such as jump location, jump form, roller length, conjugate depth ratios, and discharge ratio－behave quite differently from those of the classical hydraulic jumps.