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洪水过程中主槽平均流速和断面冲淤变化是影响下游河道排洪能力的主要因素。对黄河下游实测资料的系统分析结果表明 ,涨水期主槽平均流速随流量的增大而增加 ,但当主槽平均流速达到 2 .5m /s时 ,流速随流量的增加而增加的幅度明显减小 ,主槽平均流速和流量呈对数关系 ;洪水过程中主槽涨水期冲刷、落水期回淤 ,相应的冲淤面积与洪水流量的变幅呈较好的线性关系 ;涨水期主槽冲刷面积受含沙量的影响不明显
During the flood process, the average velocity of the main channel and the change of profile erosion and deposition are the main factors that affect the discharge capacity of the downstream channel. The results of systematic analysis of the measured data in the lower Yellow River indicate that the average velocity of main channel in the rising period increases with the increase of the flow rate. However, when the average velocity of the main channel reaches 2.5m / s, the rate of increase of the flow rate increases obviously In the process of flooding, the main channel is flush with the flood period and silt silt during the water-fall period, and the corresponding erosion and silting area shows a good linear relationship with the amplitude of flood discharge. Flushing area affected by the sediment concentration is not obvious