恒定流下均匀椭球形卵石的起动研究  

Research of Homogeneous Ellipsoid Pebbles Incipient in Steady Flow

作　　者：幸韵[1,2] 周华君[1,2] 吴国茂[1,2] 

机构地区：[1]重庆交通大学国家内河航道整治工程技术研究中心,重庆400074 [2]重庆交通大学水利水运工程教育部重点实验室,重庆400074

出　　处：《人民黄河》2014年第7期19-22,共4页Yellow River

基　　金："十二五"国家科技支撑计划项目(2012BAB05B03);重庆市教委科学技术研究项目(CSTC2011jja30002)

摘　　要：利用椭球体分析了恒定流下泥沙的起动条件，得到了椭球体卵石的无量纲起动切应力公式，建立了无量纲起动切应力与水流脉动系数、绝对隐蔽度、中轴比长轴及短轴比中轴的关系。结果表明：①通过实测资料计算出的无量纲起动切应力为0.046~0.068，说明建立的公式较为合理；②k ＝0.74、短轴比中轴为0.5时，绝对隐蔽度大于-0.5的卵石的无量纲起动切应力为0.03~0.06；当 k、短轴比中轴为定值时，随着中轴比长轴逐渐增大，无量纲起动切应力逐渐减小；在相同的中轴比长轴条件下，随着绝对隐蔽度减小，无量纲起动切应力也减小；当 k、中轴比长轴为定值时，短轴比中轴越大，无量纲起动切应力越大；③无量纲起动切应力随着内摩擦角的增大而增大；④k 越大，所需要的无量纲起动切应力越小。This article analyzed sediment incipient motion under steady flow by ellipsoid. It derived ellipsoid pebbles′equation of dimensionless in-cipient shear stress. Then,the relationship of dimensionless incipient shear stress,water ripple coefficient,relative hidden degree,medial axis to long axis and minor axis to medial axis was established. The results show that：a）the equation considers reasonable when the dimensionless incipi-ent shear stress ranges between 0. 046 ~ 0. 068 by the calculation;b）the pebbles′dimensionless incipient shear stress is 0. 03 ~ 0. 06. When k and c/ b is constant,the dimensionless incipient shear stress decreases with b/ a increasing. When b/ a in the same conditions and η ﹤ 0,the dimension-less incipient shear stress decreases with η increasing. When k and b/ a are constant,the dimensionless incipient shear stress decreases with c/ b in-creasing;c）the dimensionless incipient shear stress increases with internal friction angle increasing;d）the lager the k the less the dimensionless incipient shear stress.

关 键 词：绝对隐蔽度 水流脉动 起动切应力 卵石起动 恒定流 

分 类 号：TV142.1[水利工程—水力学及河流动力学]