中文摘要：

为研究梯形断面明渠的流速分布律,应用经过实测资料验证的三维紊流数学模型,对12种不同底坡、不同糙率以及不同宽深比组合情况下的梯形断面明渠水流流速分布进行了数值仿真.结果表明,在明渠底部内区流速分布能很好地符合对数分布,但在明渠外区流速分布更符合乘幂函数分布,等效线平均流速沿横向的分布接近于乘幂函数分布.通过最小二乘拟合,得到了梯形断面明渠垂线流速分布律和等效线平均流速横向分布律.按流速分布律计算的流速值与实测值吻合较好,表明所给出的断面流速分布律是合理可靠的,可应用于梯形断面明渠流量的精确测量.

英文摘要：

In order to study the velocity distribution in trapezoidal open channels, a 3-D turbulent numerical model, which had been verified by measured results, was used to numerically simulate the flow in 12 different kinds of trapezoidal open channels combined by different base slopes, different wall roughnesses and different aspect ratios. Results showed that the vertical distribution of flow velocity in the bottom inner region of open channel conforms to logarithmic distribution, but that in the outer region conforms to power function distribution, while the transverse distribution of equivalent mean velocity in vertical conforms to power function distribution. Through the least square fitting, laws of vertical distribution of velocity and transverse distribution of equivalent mean velocity in vertical were obtained. The velocity values calculated by the laws of velocity distribution agreed well with the measured values. Therefore, the laws of velocity distribution presented herein provide herein are reasonable and can be applied to the accurate measurement of flux of trapezoidal open channels.