3D EXPERIMENTAL STUDY OF THE MOTION OF SINGLE PARTICLES USING IMAGE-BASED TECHNIQUES

A new methodology to study the free-settling motion of single particles in a fluid at ReP 200, secondary motions such as oscillation, gliding, and tumbling occurred and caused the formation of a turbulent wake structure in the fluid surrounding the particle. Their effect on the solids velocity and drag coefficient was also quantified, being more significant on disks than on cylinders, however a direct relation between the angular orientation changes and the drag coefficient could not be suggested. It was noticed too that for irregular particles the secondary motions were not evenly defined, and that the settling may be accompanied by continuous rotations, even at low ReP, which further alter the trajectory, orientation, and surrounding fluid structure, thus complicating the quantification of the motion parameters and imposing restrictions on the visualisation systems employed here