  We experimentally examined the history dependence of the rotation-induced
granular deformation. As an initial state, we prepared a quasi-two-dimensional
granular pile whose apex is at the rotational axis and its initial inclination
is at the angle of repose. The rotation rate was increased from $0$ to
$620$~(rpm) and then decreased back to $0$. During the rotation, deformation of
the rotated granular pile was captured by a camera. From the acquired image
data, granular friction coefficient $\mu$ was measured as a function of the
ratio between centrifugal force and gravity, $\Gamma$. To systematically
evaluate the variation of $\mu$ both in the increasing (spinning up) and
decreasing (spinning down) rotation-rate regimes, surface profiles of the
deformed granular piles were fitted to a model considering the force balance
among gravity, friction, and centrifugal force at the surface. We found that
$\mu$ value grows in the increasing $\Gamma$ regime. However, when $\Gamma$ was
reduced, $\mu$ cannot recover its initial value. A part of the
history-dependent behaviors of the rotated granular pile can be understood by
the force balance model.
