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.