床面颗粒受力的脉动特性  

The Fluctuating Characteristics of Hydrodynamic Forces on Bed Particle

作　　者：王兴奎[1] 杨铁笙[1] 任裕民[1] 安凤玲[1] 

机构地区：[1]清华大学水电系,北京100084

出　　处：《水动力学研究与进展（A辑）》1993年第4期404-412,共9页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金

摘　　要：本文试验研究了床面泥沙颗料受力的脉动特性。单颗粒球体突出于床面的试验结果表明,颗粒所受的时均力与纵向时均流速的平方成线性关系。上举力系数C_l=0.296,拖曳力系数C_d=0.392,与颗粒在静水中沉降时的阻力系数相近。颗粒受力的脉动强度不到时均值的10％,脉动上举力系数C’_l=0.078,脉动拖曳力系数C_d=0.151。脉动应力的概率密度为正态分布。 梅花开紧密排列的试验结果表明,取球顶以上0.15D处实测的流速作代表流速,则C_l=0.110,C_d=0.0395。f’_l/F_l=0.434,f’_d/F_d=0.95,在这样的水流条件下,脉动应力对泥沙运动具有重要的作用。The fluctuating characteristics of hydrodynamic forces on a bed particle has been systematically studied. The test results with a single particle protruding out of bed indicates that the averaged-time forces on a particle are linear to the spectively. Fluctuating intensity of the forces on particle is less than 10 percent of the averaged-time values. Probability density of fluetuating stresses is corresponding with normal distribution. Energyspecgtrum density of fluctuating stresses in the range with high frequency is damped with - 3.1--3. 3 power offrequency. The test results with the close hexagon arrangement are similar to those with a single particle.

关 键 词：脉动特性 概率密度 水力学 床砂质 

分 类 号：TV143.1[水利工程—水力学及河流动力学]