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本文分析了非均匀沙床面形态分布特性 ,得出床面颗粒暴露度和代表粒径的方法难以反映床面糙度的特征 ,为此提出以床面高度函数 Z( x,y,t)的变化为基础 ,根据室内实验的特殊情况 ,以及主要考虑了初始和粗化床面 ,从统计理论的观点分析了床面高度变化均方差 σ,从分形理论的角度考虑了赫斯特数 Hy,分维数 Dy。由于均方差 σ,赫斯特数 Hy或分维数 Dy综合考虑了床面形态对床面糙度的影响 ,因而结合实验资料建立它们与综合糙率曼宁系数 n的相关关系 ,其结果呈现较好的相关性
In this paper, the morphological distribution characteristics of non-uniform sand bed are analyzed. It is difficult to reflect the characteristics of bed surface roughness by the method of exposing the grain and representing the particle size of the bed. In this paper, the bed height function Z (x, y, t) According to the special case of indoor experiment, and considering the initial and coarse bed, the mean square deviation of bed height was analyzed from the statistical theory point of view, and the Hurst number Hy , Fractal dimension Dy. Since the mean square deviation σ, the Hurst number Hy or the fractal dimension Dy take into account the effect of the bed shape on the bed surface roughness, the correlation between them and the Manning coefficient n of the comprehensive roughness is established based on the experimental data. The results show that Good correlation