【作者】 王兴奎；

【导师】 钱宁；

【作者基本信息】 清华大学 ， 水力学及河流动力学， 1985， 博士

【摘要】 本文研制的浑水脉动流速仪具有良好的静、动态特性。信号处理系统能在通用计算机上计算-维随机变量的各种统计参数。这一量测分析系统将有助于对浑永紊动结构的深入研究。浑水时匀流速分布可分成两个流区，两个流区的分布均遵循对数规律，只是相应的卡门常数有所不同。由中性悬浮质组成的伪一相流的流速分布也存在同-趋势。与均质流的流速分布迥然不同。影响流速分布的主要因素有底部粘度、颗粒格栅阻尼和密度梯度。据此导出了两个流区的时均流速分布公式，给出了卡门常数的数学表达式，误差小于15％。悬沙浓度分布仍遵循扩散定律，但扩散指教Z1将受到颗粒群体沉速和离散力的影响，-般为y的函数。与清水相比较，浑永的紊动强度减小，频率降低，但基本紊动结构并不改变。在试验所采用的泥沙级配的条件下，悬沙水流的阻力特性与清水一致。更多还原

【Abstract】 The sediment-laden flow fluctuating velocimeter designed in this study has a well static and dynamic charateristic. The system of signal treatment may be used to calculate various one-dimentional. statistical factors by computer. This system of measurement and analysis may prove to be beneficial, to the investigation of turbulent structure of the sediment-laden flow.The mean velocity profile of sediment-laden flow can bet divided into two regions. The profiles for both regions follow the logarithmic law. Only the Von Karman universal constants are different from each other. EveiL the velocity profile of the pseudo one-phase flow consisting of neutrally buoyant particles also follows the same tendency, and is utterly different from that of the homogeneous flow. The maim factors affecting the velocity profiles are the viscosity near the bed, particle grid resistance and the density gradient. Formulas of the mean velocity profiles of the two regions can be developed on the basis of this physicalmodel, and the expression of the Von Karman universal, constant is given with an error of less than 15 % .The distribution of concentration still obeys the diffusion law, only the efftects of the group particle fall velocity and the dispersive force on the diffusion index Z1 shall be considered. Generally, Z1 is a function of the height y .The turbulent intensity and frequency of the sediment-laden flow are less than those of the clear water flow, but the fundamental structure of the flow remains unchanged.The frictional resistance of the sediment-laden flow is essentially the same as that of the clear water flow within the range of size distribution of sediment used in our experiments.更多还原