兰州大学机构库 >土木工程与力学学院
风沙起动规律的研究
Alternative TitleThe research of the initlation thresholds of blown sand
龚昌财
Thesis Advisor黄宁
2010-05-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword非均匀沙 起动风速 相对暴露度系数 附加质量力 隶属函数
Abstract本学位论文主要对两个问题进行了研究:针对非均匀沙的大小颗粒之间的荫暴作用,提出了考虑相对暴露度和颗粒组成影响下的非均匀沙起动公式;针对目前坡面非均匀沙起动的复杂性和随机性,用确定性方法建立起动风速公式并对公式进行了验证和分析,在此基础上将模糊数学方法引入均匀沙的起动风速,采用滑动平衡模型建立了考虑气流紊动影响和起动水平时的坡面非均匀沙起动风速公式,并做了简单分析。 首先借鉴泥沙研究非均匀沙起动的方法,本文从非均匀沙起动的特点出发,对床面风沙颗粒的绝对暴露度 及相对暴露度系数 进行了定义,并对其取值进行了理论分析,结果表明床面表层风沙颗粒的相对暴露度取值并非常量,而是位于一个区间。考虑相对暴露度和颗粒组成的影响提出附加质量力的概念及表达式并将相对暴露度参数的引入,推出了非均匀沙起动公式。并用实测资料进行了验证,说明本文公式较好的反映了非均匀沙的起动特性。 针对目前对坡面非均匀沙理论和实验研究较少的现状,借鉴泥沙方面的研究方法,在考虑暴露度影响下,引入附加质量力,采用滑动平衡模式,用确定方法建立了坡面非均匀沙起动风速公式,并和特殊状态下、即坡角为零时试验资料进行了对比,发现和试验吻合数据较好。在用确定方法建立的坡面非均匀沙起动风速公式基础上,借助模糊数学方法,采用滑动平衡模型建立了考虑气流紊动影响和起动水平时的坡面非均匀沙起动风速公式,并做了简单分析。
Other AbstractThis dissertation mainly focus on two problems as follows: aimed on the shading interaction of non-uniform sand particles, proposed a formula of non-uniform sand’s threshold velocity by considering the relative exposure degree and particle composition. Because of the complexity and randomicity of the non-uniform sand’s threshold velocity on slope, the slide balance mode was used to constitute the formula of non-uniform sand’s threshold velocity of slope, then this formula was validated and analyzed. Based on above analysis, a formula with consideration of air turbulence and threshold level was established through the fuzzy mathematics method and slide balance mode, and simply analysis was made.First using the method of the inhomogeneous sand initiation in silt research for reference, this article starts from the initiation characteristics of the inhomogeneous sand,and defines the exposure degree and Coefficient of relative exposure degree. And the theoretical analysis has been carried on the values of the exposure degree and Coefficient of relative exposure degree. The result indicates that the relative exposition value of bed surface layer sandstorm pellet is not a constant, but is located in a sector. Then through considering the relative exposure degree and particle composition we propose the concept and expression of additional mass force with reference to the method of sediment threshold velocity and can the formula of threshold velocity are gotten by introducing the relative exposure degree parameter. Compared to the experimental data, we can see that the formula in this paper can show the threshold characteristic of non-uniform sand particles well.At present the theory and experimental study on the movement of inhomogeneous sand on slope face are very few. In this dissertation, through introducing the additional mass force and the slide balance mode, a formula of non-uniform sands threshold velocity of slope is constituted with consideration of the effect of exposure degree.The experimental data is compared with the results from this dissertation for zero slope angle and it is found that the results from this dissertation agree well with experimental data. Based on the formula of non-uniform sand’s threshold velocity of slope, we establish the formula with consideration of air turbulence and threshold level through the fuzzy mathematics method and slide balance mode, and simply analysis is then made.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226511
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
龚昌财. 风沙起动规律的研究[D]. 兰州. 兰州大学,2010.
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