Granular dynamics of a vibrated bed of dumbbells

• Published in: The European physical journal. ST, Special topics Vol. 179; no. 1; pp. 5 - 17
• Main Authors: Wildman, R.D., Beecham, J., Freeman, T.L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-12-2009
• Subjects: Atomic; Classical and Continuum Physics; Computer programs; Computer simulation; Condensed Matter Physics; Density; Materials Science; Mathematical analysis; Mathematical models; Measurement Science and Instrumentation; Molecular; Optical and Plasma Physics; Particulate composites; Physics; Physics and Astronomy; Position (location); Regular Article; Velocity distribution; Hough Transform; European Physical Journal Special Topic; Packing Fraction; High Speed Photography; Velocity Distribution
• ISSN: 1951-6355; 1951-6401
• DOI: 10.1140/epjst/e2010-01189-y

A two-dimensional vibrated bed of dumbbells was investigated using experiment and numerical simulation. Experimentally, high speed photography in combination with image analysis and tracking software was used to determine the location of the centre of mass and the locations and direction of motion of the component particles of the dumbbells. Numerically, a geometry analogous to that used experimentally was employed and the equations of motion for each of the particles were solved using the distinct element method. It was found that, despite some differences, the numerical simulations agreed reasonably well with the experimental results. Subsequently, the simulation method was used to explore the behaviour of the bed over a range of densities. The moments of the velocity distributions were determined as a function of height for a range of numbers of particles, and it was found that a normal distribution of velocities is a good approximation, except close to the vibrating base where there were suggestions that the distribution of the vertical component of the velocities is a composite of two sets of particles, one pre-collision with the base, and the other post-collision.