Effect of Particle Shape on Fall Velocity of Angular Particles

In this study, fall velocities of 174 regularly shaped angular particles—namely cylindrical, cubic, wedge-shaped prisms, and boxshaped prisms—made of five different materials were measured in calm water conditions in a cylindrical settling column. Reynolds numbers based on particle fall velocity and characteristic length were varied, in the range from 103 to 4.2 × 104. A new shape factor and characteristic length were defined from a transformed form of the original particle. Variation of experimentally obtained data of particle drag coefficient, C*D, with Reynolds number, *, as a function of newly defined shape factor and characteristic length was analyzed. Verification was made by using experimental data of irregular angular particles. The results showed that the fall velocity of any irregular angular particle could be estimated by using graphical curves obtained from the analysis of the regular angular particles.