Figure 2
From: Spreading of triboelectrically charged granular matter
Transverse density modulation.
(A) The appearance of a modulation in the density of stuck particles (d = 300 μm) with a periodicity in the azimuthal angle in polypropylene vial. Top and bottom panel shows static and dynamic images at a sequence of times marked above the images. The periodicity of the modulation depends on the frequency of the orbital motion and the size of the particles. (B) shows this periodic modulation at frequencies 14 Hz, 20 Hz, 25 Hz, 30 Hz and 40 Hz. For certain frequencies (14 Hz, 30 Hz) we observe more pronounced stripes which weaken substantially for intermediate values of f (20 Hz, 25 Hz and 40 Hz). Inset shows the dependence of the wavelength of the periodic modulation, Λ, on the particle diameter, d, at f = 14 Hz.
