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工程科学与技术:2008,40(5):51-57
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非均匀沙分级起动流速研究
(四川大学 水力学与山区河流开发保护国家重点实验室,四川 成都,610065)
Study on Incipient Velocity of Individual Fradctions of Non-uniform Sediment
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投稿时间:2007-10-16    
中文摘要: 非均匀沙对均匀沙明显不同,对非均匀沙起动机理作了分析,运用概率论与力学相结合的方法,以现有的相对暴露度为基础导出了泥沙颗粒力臂的数学期望,进而导出了考虑非均匀沙隐暴效应的起动概率表达式。在采用的细颗粒暴露度的分布函数上存在一间断点,从泥沙运动机理和数学上证明了它对力臂的数学期望没有影响。在起动概率的基础上建立了第l级粒径的起动公式。通过现有的非均匀沙起动流速试验资料,确定了计算公式的参数。同时用现有的实验资料对作者起动流速公式进行验证,并且同其它流速公式相比较可以看出作者的起动流速公式预测精度较高。作为特例,同时也得到了均匀沙的起动公式。
Abstract:There is obvious difference of transport mechanism between the uniform and non uniform sediment, in this paper, the incipient motion of non-uniform sediment is theoretically studied, based on the method of probability theory combined with mechanics, the mean of sediment particle’s force arm and the expression for the probability of incipient motion with shelter-exposure effects to be considered are derived. There is a discontinuity point in Han’s fine sediment distribution function, based on the sediment motion mechanism and L-S integral property, author bears out that it does not influence the mean of force arm. Once the incipient probability is built, the incipient velocity can be determined. From the experiment for the incipient motion of non uniform sediment with colored sand conducted by Han, the coefficients in the computational formula are determined. Verifications with Han’s experiment data show that the theoretical formula is better than Han’s. The computed results fully reflect the characteristics of threshold motion of non-uniform sediment.Finally the formula of uniform sediment is established, as a special case.
文章编号:20080509     中图分类号:    文献标志码:
基金项目:国家自然科学基金项目(50579041);国家自然科学基金项目(50579040)
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引用文本:
杨奉广,曹叔尤,刘兴年.非均匀沙分级起动流速研究[J].工程科学与技术,2008,40(5):51-57.
.Study on Incipient Velocity of Individual Fradctions of Non-uniform Sediment[J].Advanced Engineering Sciences,2008,40(5):51-57.