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通过理论分析与数值计算,研究了冲积河流漫滩水流水力因子的变化特性。结果表明,断面平均流速在漫滩瞬间迅速减小,然后逐渐增大;断面综合动能修正系数、动量修正系数均随水深而缓慢增加,在漫滩瞬间迅速增大,随即快速减小。根据漫滩水流水力因子沿水深的变化特性,提出采用断面横向平均流速为判别因子以定量划分复式断面的滩与槽。此外,文中将其应用于黄河下游漫滩水流的水沙数值模拟,其结果与实际情况符合较好。
Through theoretical analysis and numerical calculation, the variation characteristics of hydrodynamic factors of floodplain in alluvial river are studied. The results show that the mean velocity decreases rapidly at the instant of floodplain and then increases gradually. The comprehensive kinetic correction coefficient and momentum correction coefficient increase slowly with water depth and rapidly increase at floodplain, then decrease rapidly. According to the variation characteristics of hydrodynamic factors of floodplain along the water depth, the transverse flow rate across the cross section is taken as the discriminant to quantitatively divide the beach and the trough of the multi-section. In addition, it is applied to the numerical simulation of water and sediment in the floodplain in the lower Yellow River. The result is in good agreement with the actual situation.