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通过开展挟沙水流试验,对河槽断面的纵向时均流速横向与垂向分布、瞬时流速频率分布、紊动强度垂向分布规律进行了研究,最后分析了断面宽深比对张瑞瑾公式的影响.得出如下结论:在相同横断面面积、流量情况下,随着断面宽深比的减小,准二维流动的中心区所占河宽比例减小,断面流速分布更加趋中;挟沙水流主流区流速垂向分布基本上仍然符合对数分布,随着含沙量的增大,卡门常数k有减小的趋势;中垂线上各点瞬时流速频率分布基本上符合正态分布;靠近水面处紊动强度最弱,紊动强度随相对水深的减小而增大,随后紊动强度随相对水深的减小而减小;随着断面宽深比的减小,张瑞瑾公式中的系数呈增加的趋势,流量幂指数呈减小的趋势.
Through carrying out sediment-laden flow test, the horizontal and vertical distributions of longitudinal average flow velocity, the vertical distribution of instantaneous flow velocity and the vertical distribution of turbulence intensity are studied. Finally, the influence of aspect ratio on the formula of Zhang Ruijin is analyzed. The conclusions are as follows: With the same cross-sectional area and flow rate, with the reduction of width-to-depth ratio, the ratio of river width in the center of quasi two-dimensional flow decreases, The vertical distribution of flow velocity in the mainstream area is still basically in line with the logarithmic distribution. With the increase of sediment concentration, the Carmen constant k tends to decrease. The instantaneous flow velocity distribution at each point in the vertical distribution basically meets the normal distribution. The turbulent intensity at the water surface is the weakest, the turbulence intensity increases with the decrease of the relative water depth, and then the turbulence intensity decreases with the decrease of the relative water depth. As the aspect ratio decreases, the coefficient in Zhang Ruijin’s formula Showed an increasing trend, power flow index showed a decreasing trend.