水库异重流潜入点流速分布及其判别式改进

摘要

异重流潜入条件是判断异重流是否潜入的数学表达.异重流潜入条件中含沙量与潜入弗劳德数为隐性关系,是由于以往研究对潜入点垂线流速分布未能给出适当的数学表达式,无法直接分离弗劳德数中含沙量因子.通过对异重流潜入点处垂线流速分布物理图形的数学分析,得到潜入点处垂线流速分布理论公式形式为抛物线;利用小浪底水库2001-2015年调水调沙期异重流潜入点资料,率定得到潜入点处垂线流速分布公式的经验系数,理论公式与经验公式二者系数值接近,揭示了理论假设的正确.代入水库浑水异重流潜入动量修正系数公式,分别确定其理论值为1.2、小浪底水库实测值为1.13,均为常数,二者也颇为接近.在此基础上,采用范家骅[13]、曹如轩[14]、焦恩泽[15]等水槽试验资料、2001-2005小浪底水库实测资料和模型试验资料验证,推导获得了新的水库异重流潜入点判别关系式,并利用2006-2015年小浪底水库和1961-1962年三门峡水库实测资料进行了预测计算,结果表明,新的潜入条件计算的潜入点水深与实测值更加接近,更符合实际.该成果可为多沙河流水库调水调沙预案编制和水库异重流数学模拟提供技术支撑.%The discriminant formula is a mathematics formula which can decide whether turbidity current plunges.There are an implicit relation between in the discriminant of plunging point,due to the past researchers ignoring or hard to give the mathematics formula on the vertical velocity distribution at the point which could not directly discrete sediment content from Froude number.With mathematic analysis on surveyed data and experiments,physical figure of vertical velocity distribution was decided by parabola.Based on plunging point data during water and sediment regulation period in Xiaolangdi reservoir in 2001 to 2015,and data from tests on physical model of Xiaolangdi reservoir,empirical coefficient of the vertical velocity distribution formula at the point was acquired with calibration,which revealed the theoretical hypothesis was right.Then the momentum correction factor of turbidity current in reservoir is obtained respectively by 1.2 in theory and 1.13,which were closely.Based on the above research,an improved discriminant formula is validated by the data of flumes by Fan Jiahua[13],Cao Ruxuan[14] and Jiao Enze[15],surveyed data of Xiaolangdi reservoir in 2001 to 2005,and data from tests on physical model of Xiaolangdi reservoir.The prediction results of the formula by data from Xiaolangdi reservoir and Sanmenxia reservoir were pretty well with the surveyed.This could be applied in water and sediment regulation program compilation and numerically simulating in sediment-laden reservoirs.