FALL VELOCITY OF IRREGULAR SHAPED PARTICLES

The determination of the free-fall velocity of irregularly shaped particles in viscous fluids is presented. A shape parameter is proposed which correlates Reynolds number with drag coefficient to describe the motion of irregular shapes. This shape parameter results in a useful Reynolds number-drag coefficient relation. Data for analysis were collected from tests of natural gravel-sized particles of various shapes and sizes supplemented by larger regular geometric shapes. The basic motions of a particle in free-fall are classified and analyzed considering causes such as flow separation and vortex formation.