考虑底坡的异重流倒灌流量计算公式

水库异重流倒灌是造成支流淤积的重要原因,影响支流库容可持续利用。已有的异重流倒灌流量公式在推导过程中均假设支流底坡为0,所计算的倒灌流量往往大于实测值。本文通过在倒灌异重流的动量方程中加入底坡上的压力,推导了考虑底坡的异重流倒灌流量公式。公式结构形式表明在相同的口门浑水厚度与含沙量条件下,倒灌流量随底坡增加而减小。使用小浪底水库4条支流的异重流测验数据对公式进行了验证。验证结果表明相对于不考虑底坡的倒灌流量公式,本文提出的公式计算精度更高。

A discharge formula of turbidity current intruding into a tributary with the effect of bed slope

Turbidity current intruding into the tributaries pose an influence to the sustainable use of the storage capacity of tributary in a reservoir.Existing formulas for estimating discharge of turbidity current intruding into a tributary usually assume a horizontal channel bed,and they are apt to overestimate the intrusion discharge.A formula to calculate the intrusion discharge involved with bed slope effect was established by introducing the pressure on the tilted tributary bed in the momentum equation for turbidity currents.As indicated by the formula,the intrusion discharge decreases as the bed slope of the tributary increases at given depth and sediment concentration of the turbid flow at the tributary entrance.The formula was verified using field observations of turbidity currents intruding into four tributaries of the Xiaolangdi Reservoir.The proposed formula was demonstrated to produce better prediction to intrusion discharge than those neglecting the bed slope effect.