均匀推移质泥沙起动概率量化分析
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摘要
采用泥沙滚动起动模式,考虑了床面泥沙暴露度及近底水流的随机性,从理论上推导出了推移质泥沙的起动概率公式。此起动概率是床面泥沙颗粒暴露度(或暴露角θ)和近底瞬时流速的函数,其大小随着泥沙暴露度和近底瞬时流速的变化而变化,这与以往学者得到的泥沙起动概率存在较大区别。经与实测资料对比,验证了本文所求的起动概率的正确性。依据冲刷率与起动概率之间关系,将本文所求起动概率转化为无量纲冲刷率,进一步通过实测资料验证了所求起动概率的合理性。
Based on rolling mode, considering randomness of exposure angle of bedload and near-bed instantaneous velocity, an entrainment probability formula have been derived. This entrainment probability is a function of the bed particle exposure degree(or exposure angle θ) and near-bed instantaneous velocity u_b, which depends not only on the near-bed instantaneous velocity u_b, but also on the sediment exposure degree or exposure angle θ. This is quite difference from the entrainment probability obtained by the previous scholar. Comparing with the measured data, the correctness of the entrainment probability is verified. According to the relationship between the pick-up rate and the entrainment probability, the entrainment probability in this paper is transformed into the dimensionless pick-up rate, and the rationality of the entrainment probability is verified by the measured data.
Based on rolling mode, considering randomness of exposure angle of bedload and near-bed instantaneous velocity, an entrainment probability formula have been derived. This entrainment probability is a function of the bed particle exposure degree(or exposure angle θ) and near-bed instantaneous velocity u_b, which depends not only on the near-bed instantaneous velocity u_b, but also on the sediment exposure degree or exposure angle θ. This is quite difference from the entrainment probability obtained by the previous scholar. Comparing with the measured data, the correctness of the entrainment probability is verified. According to the relationship between the pick-up rate and the entrainment probability, the entrainment probability in this paper is transformed into the dimensionless pick-up rate, and the rationality of the entrainment probability is verified by the measured data.
引文
[1] Einstein H A.The bed load function for sediment transportation in open channel flows [M].北京:水利出版社,1950.
[2] 钱宁,万兆惠.泥沙运动力学[M].北京:科学出版社,1983.
[3] 孙志林,祝永康.Einstein推移质公式探讨[J].泥沙研究,1991(1):20-26.
[4] 张小峰,谢葆玲.泥沙起动概率与起动流速[J].水利学报,1995(10):53-59.
[5] Cheng N S,Chiew Y M.Pickup probability for sediment entrainment [J].Journal of Hydraulic Engineering,1998,124(2):232-235.
[6] Wu F C,Chou Y J.Rolling and lifting probabilities for sediment entrainment [J].Journal of Hydraulic Engineering,2003,129(2):110-119.
[7] Wu F C,Lin Y C.Pickup probability of sediment under log-normal velocity distribution [J].Journal of Hydraulic Engineering,2002,128(4):438-442.
[8] Wu F C,Yang K H.Entrainment probabilities of mixed-size sediment incorporating near-bed coherent flow structures [J].Journal of Hydraulic Engineering,2004,130(12):1187-1197.
[9] 何文社,方铎,曹叔尤,等.泥沙起动判别标准探讨[J].水科学进展,2003,14(2):143-146.
[10] Paintal A S.A stochastic model of bed load transport [J].Journal of Hydraulic Research,1971,9(4):527-554.
[11] 韩其为.泥沙起动规律及起动流速[J].泥沙研究,1982(2):11-26.
[12] 何文社,曹叔尤,刘兴年,等.泥沙起动临界切应力研究[J].力学学报,2003(3):326-331.
[13] 何文社,杨具瑞,方铎,等.泥沙颗粒暴露度与等效粒径研究[J].水利学报,2002(11):44-48.
[14] 杨奉广,刘兴年,黄尔,等.唐家山堰塞湖下游河床泥沙起动流速研究[J].四川大学学报(工程科学版),2009,41(3):84-89.
[15] 邢茹,张根广,梁宗祥,等.床面泥沙位置特性试验研究——暴露角、纵向水平间距及相对暴露度概率密度分布[J].泥沙研究,2016(4):28-33.
[16] 周双,张根广,王新雷,等.均匀泥沙相对暴露度的试验研究[J].泥沙研究,2015(6):40-45.
[17] 韩其为,何明民.泥沙起动规律及起动流速[M].北京:科学出版社,1999.
[18] Yalin M S.Mechanics of sediment transport [M].Oxford Pergaman Press,1972.
[19] Rijn L C V.Sediment transport,Part I:bed load transport [J].Journal of Hydraulic Engineering,1984,110(10):1431-1456.
[20] Rijn L C V.Sediment pick functions [J].Journal of Hydraulic Engineering,1984,110(10):1494-1502.
[2] 钱宁,万兆惠.泥沙运动力学[M].北京:科学出版社,1983.
[3] 孙志林,祝永康.Einstein推移质公式探讨[J].泥沙研究,1991(1):20-26.
[4] 张小峰,谢葆玲.泥沙起动概率与起动流速[J].水利学报,1995(10):53-59.
[5] Cheng N S,Chiew Y M.Pickup probability for sediment entrainment [J].Journal of Hydraulic Engineering,1998,124(2):232-235.
[6] Wu F C,Chou Y J.Rolling and lifting probabilities for sediment entrainment [J].Journal of Hydraulic Engineering,2003,129(2):110-119.
[7] Wu F C,Lin Y C.Pickup probability of sediment under log-normal velocity distribution [J].Journal of Hydraulic Engineering,2002,128(4):438-442.
[8] Wu F C,Yang K H.Entrainment probabilities of mixed-size sediment incorporating near-bed coherent flow structures [J].Journal of Hydraulic Engineering,2004,130(12):1187-1197.
[9] 何文社,方铎,曹叔尤,等.泥沙起动判别标准探讨[J].水科学进展,2003,14(2):143-146.
[10] Paintal A S.A stochastic model of bed load transport [J].Journal of Hydraulic Research,1971,9(4):527-554.
[11] 韩其为.泥沙起动规律及起动流速[J].泥沙研究,1982(2):11-26.
[12] 何文社,曹叔尤,刘兴年,等.泥沙起动临界切应力研究[J].力学学报,2003(3):326-331.
[13] 何文社,杨具瑞,方铎,等.泥沙颗粒暴露度与等效粒径研究[J].水利学报,2002(11):44-48.
[14] 杨奉广,刘兴年,黄尔,等.唐家山堰塞湖下游河床泥沙起动流速研究[J].四川大学学报(工程科学版),2009,41(3):84-89.
[15] 邢茹,张根广,梁宗祥,等.床面泥沙位置特性试验研究——暴露角、纵向水平间距及相对暴露度概率密度分布[J].泥沙研究,2016(4):28-33.
[16] 周双,张根广,王新雷,等.均匀泥沙相对暴露度的试验研究[J].泥沙研究,2015(6):40-45.
[17] 韩其为,何明民.泥沙起动规律及起动流速[M].北京:科学出版社,1999.
[18] Yalin M S.Mechanics of sediment transport [M].Oxford Pergaman Press,1972.
[19] Rijn L C V.Sediment transport,Part I:bed load transport [J].Journal of Hydraulic Engineering,1984,110(10):1431-1456.
[20] Rijn L C V.Sediment pick functions [J].Journal of Hydraulic Engineering,1984,110(10):1494-1502.