top of page

Volumetric Measurements Of Particle-Wake Interactions

Yi Hui Tee, James R. Dawson, R. Jason Hearst

Norwegian University of Science and Technology (NTNU), Trondheim, Norway


Research on freely falling particles has primarily focused on wake dynamics and vortex shedding of individual particles in quiescent flow. When these particles fall collectively, the wakes of surrounding particles alter the flow fields. Hence, we conducted volumetric experiments to investigate how the settling and wake dynamics of particles are affected by the wakes of other settling particles. Negatively buoyant 12 mm particles of (sphere, flat cuboid, circular and square cylinders) are first released individually into quiescent water. Then, the particles are released individually into the bulk wakes of 20 mono-dispersed particles. Using four high-speed cameras and LEDs, we simultaneously capture both 3D particle and fluid motions in the terminal velocity regime. The imaging domain measures 90 mm x 90 mm x 40 mm. Our results show that all trailing particles settling through the bulk wakes gain additional downward momentum from the turbulent wakes, falling faster than in the quiescent flow. Upstream of the particle, the vortices in the bulk wake interact with the developing shear layer along the particle. The wake downstream of the trailing particle also appears more chaotic than that in a quiescent flow.

bottom of page