悬移质颗粒运动的脉动强度

应用图象处理技术,量测了直径d=0.1～1.5mm的塑料颗粒和d=0.1～0.3mm的玻璃球颗粒在明槽恒定均匀水流中运动的脉动强度.试验发现:(1)靠近床面处,粗颗粒的脉动强度大于细颗粒的脉动强度,在靠近水面处,规律则相反;(2)细颗粒的脉动强度只是相对水深y/h的函数,而粒径较大颗粒的脉动强度和y/h及摩阻流速都有关;(3)重颗粒的脉动强度小于相同粒径的轻质颗粒的脉动强度.

Experimental study on velocity fluctuations of suspended particles

The image processing technique was applied to measure velocity fluctuations of suspended parti cles in open channel flows. Two kinds of spherical particles were studied:plastic particles(d=0.1~1.5 mm)and glass particles(d=0.1~0.3 mm)Experimental results reveal that:(1)coarse particles pos sess greater velocity fluctuations than fine particles in the near bed region,while the scenario is completely opposite in the upper flow;(2)the velocity fluctuation of fine particles is a function of y/h,and for coarse particles,the velocity fluctuat ions relate not only to y/h but also to the shear stress;and(3)the plastic particles have greater velocity fluctuations than glass particles of the same size.