考虑底坡的异重流倒灌流量计算公式
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摘要
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。
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.
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.
引文
[1]韩其为.水库淤积[M].北京:科学出版社,2003.
[2]张俊华,马怀宝,王婷,等.小浪底水库支流倒灌与淤积形态模型试验[J].水利水电科技进展,2013,33(2):1-4+25.
[3]范家骅.异重流与泥沙工程试验与设计[M].北京:中国水利水电出版社,2011.
[4]张俊华,陈书奎,李书霞,等.小浪底水库拦沙初期水库泥沙研究[M].郑州:黄河水利出版社,2007.
[5]金德春.浑水异重流的运动和淤积[J].水利学报,1981(3):39-48.
[6]秦文凯,府仁寿,韩其为.反坡异重流的研究[J].水动力学研究与进展,1995,10(6):637-647.
[7]Benjamin T B.Gravity currents and related phenomena[J].Journal of Fluid Mechanics,1968,31(2):209-248.
[8]Li Y,Zhang J,Ma H.Analytical Froude number solution for reservoir density inflows[J].Journal of Hydraulic Research,2011,49(5):693-696.
[9]李树森,郑宝旺,樊东方,等.黄河小浪底水库水文泥沙规律研究[M].郑州:黄河水利出版社,2014.
[2]张俊华,马怀宝,王婷,等.小浪底水库支流倒灌与淤积形态模型试验[J].水利水电科技进展,2013,33(2):1-4+25.
[3]范家骅.异重流与泥沙工程试验与设计[M].北京:中国水利水电出版社,2011.
[4]张俊华,陈书奎,李书霞,等.小浪底水库拦沙初期水库泥沙研究[M].郑州:黄河水利出版社,2007.
[5]金德春.浑水异重流的运动和淤积[J].水利学报,1981(3):39-48.
[6]秦文凯,府仁寿,韩其为.反坡异重流的研究[J].水动力学研究与进展,1995,10(6):637-647.
[7]Benjamin T B.Gravity currents and related phenomena[J].Journal of Fluid Mechanics,1968,31(2):209-248.
[8]Li Y,Zhang J,Ma H.Analytical Froude number solution for reservoir density inflows[J].Journal of Hydraulic Research,2011,49(5):693-696.
[9]李树森,郑宝旺,樊东方,等.黄河小浪底水库水文泥沙规律研究[M].郑州:黄河水利出版社,2014.