【摘要】 本文根据水槽试验和统计分析,探讨了泥浆湍流的脉动流速概率密度分布和各阶矩,自相关系数及频谱分布。泥浆湍流底部为间歇湍流层,偏态系数为正,而强脉动层上部和扩散层偏态系数为负,说明紊动产生于强脉动层下部（y⁺=3—10）,由于间歇紊动,分布曲线出现双峰,泥浆湍流自相关系数R显著大于清水,R（t）曲线呈波状,说明流速的脉动部分来自规则的波动。泥浆湍流的频谱分布迥异于清水流。1Hz左右的低频脉动能量在清水湍流中为10—20％,泥浆湍流中则达40—50％,浓度很高（265kg/m³）时高达70％,同时在2—20Hz的主频范围内,能谱密度G（n）在清水湍流中有关系G（n）-n^-6-5,而泥浆湍流中则演变成G（n）n-^-（2-7）。更多还原

【Abstract】 Based on the measurement and statistical analysis on turbulent velocity of Bingham fluid flow, the probability density distribution of fluctuating velocity, the autocorrelation coefficient R(t) and the spectral density distribution of Bingham fluid turbulent flow are studied. The distribution of turbulent intensity of Bingham fluid flow is far more ununiform than water flow. The probability density distribution of fluctuating velocity is of positive value in the intermittent turbulent layer and of negative value in the high-intensive turbulent layer. This implies that the turbulence in Bingham fluid flow is produced somewhere between the two layers. Intermittent turbulence in the intermittent turbulent layer and the diffusion layer results in bimodal probability density distribution. The autocorrelation coefficient R(t) in Bingham turbulent flow is much larger than turbulent water flow, and the R(t) curve assumes a wavy form sometimes which suggests that the fluctuation in velocity in Bingham turbulent flow partly results from regular waves. The spectral density distribution of Bingham fluid turbulent flow is more and more disparate with Newtonian turbulent flow following increase in the yield stress and rigidity coefficient of the fluid. 40-50%, and even 70% sometimes, of turbulent energy concentrates in low frequency turbulent eddies, compared with 10-20% of the energy in low frequency turbulent eddies in water flow. The spectral density distribution shows a power law relation G(n)-n-(2-r) in the range of 2-20 Hz for the Bingham turbulent flow, which is quite different from that of clear water flow (G(n)-n-0.8).更多还原