Application of Particle Image Velocimetry for velocity measurements during silo discharge

The objective of this paper is the measurement of dynamic effects and bulk solid flow profiles in silos using the optical method Particle Image Velocimetry. A sequence of digital images of the moving bulk solid next to the wall in a model silo is analysed. The frame rate between consecutive images and the calculated displacements of particles lead to velocity profiles. The fluctuation of local velocities with time is determined with this method providing insight into the dynamic behavior of the flowing bulk solid. The fluctuations of bulk solids motion lead to changes of the wall stresses measured in a model silo with special load cells. The velocity measurements are combined with stress measurements at the silo walls. The experimental results are compared with results from numerical simulations.