  Shear induced orientational ordering of asymmetric elongated particles is
investigated experimentally. Corn grains and pegs with one end sharpened are
studied using X-ray Computed Tomography (CT) during quasistatic shearing and
silo discharge. We show that asymmetries can be detected in the orientational
distributions of the particles, which are related to the modulated rotation of
the particles during shear flow. Namely, when the particles rotate in a plane
that is not horizontal, they spend more time with the sharper (lighter) end
pointing up, which can be explained using energetic arguments. We quantify the
resulting asymmetry of the orientational distribution in a split bottom Couette
cell and in a silo discharge process.
