Mass Transfer from Non-Spherical Particles in Turbulence

Inertial, non-spherical particles in turbulent flows show interesting kinematic properties such as the difference between tumbling and spinning rates depending on size, and overall enstrophy being shape independent. While kinematics have been studied for many different types of Taylor-scale, non-spherical particles such as fibers, flat particles, and cuboids, to our knowledge, no dissolving non-spherical particles have been studied in the same size range. In this study, we present results for rod-like and disc-like neutrally buoyant particles that dissolve in water. The particles we tested were designed to explore the shape-motion-flux relationship through a variety of surface areas, volumes, and aspect ratios. Throughout the parameter space tested, we found that between rods and discs, disc-like particles dissolved faster than rod-like particles. However, within the parameter spaces of rod-shaped particles that were tested, the rods’ dissolution rate decreased as the surface-area-to-volume ratio decreased. This suggests that the surface-area-to-volume ratio could be the governing factor characterizing dissolution rates within particles of the same shape, but not between particles of different shapes.