基于三维泥沙颗粒相对隐蔽度的底坡上散体沙起动初步研究

Preliminary research on incipient motion of 3-D hidden cohesionless sediment particles on bed slope

以三维泥沙颗粒相对隐蔽度为基础,推导了以颗粒隐蔽度和床面坡度为参数的散体沙起动流速公式,证明了宽级配散体非均匀沙的起动特性,论证了一系列诸如"完全隐蔽"、"极限跳跃"、"临界暴露"等概念的物理意义,分析了紊流粗糙区Shields带状曲线的成因,最后建立了底坡上散体均匀沙起动条件不同起动标准下对应的数值关系,并进行了讨论。

Based on the research on 3-D hidden sediment particles and by adopting the parameters of hidden degree and bed gradient, the formula of the incipient velocity is deduced and the incipient characteristics of non-uniform sediment are proved. A series of concepts, such as‘completely hidden＇ , ‘extreme jump＇ ,‘pseudo completely hidden＇ , ‘ critical exposure＇ , etc. , are proposed, and the corresponding mathematical expressions are deduced. Finally, the reason for the scattering of data in Shields diagram is proposed, the numerical relations between the hidden degree and incipient motion conditions are established, and some discussions are introduced.