沙波当量粗糙度的分形特性初探

摘要

应用分形维数描述不规则沙波床面形态的复杂性，基于室内水槽定床试验资料，建立了沙波当量粗糙度的分形表达式，获得了无量纲沙波当量粗糙度与床面形态分形维数及相对波高之间的关系式，并对公式进行了分析和比较。结果表明：该公式较好地反映了沙波床面三维特征对沙波当量粗糙度的影响，可用于沙波当量粗糙度的预估研究。%Fractal dimensions were used to descript the bedform’s irregularity and complexity,based on immovable bed experimental investigations, the fractal expression of bedform equivalent roughness was developed,and the relation between non-dimensional equivalent roughness,fractal dimen-sion and relative height were obtained. Finally,the fractal expression was compared by some representative formulas,along with the disscusion to it. The results indicate that the expression can better reflect the influence of bedform’s three-dimensional characteristics to the equivalent roughness.