  We measure the torque acting on a rod rotated perpendicular to its axis in a
granular bed, through which an upflow of gas is utilized to tune the
hydrostatic loading between grains. At low rotation rates the torque is
independent of speed, but scales quadratically with rod-length and linearly
with depth; the proportionality approaches zero linearly as the upflow of gas
is increased towards a critical value above which the grains are fluidized. At
high rotation rates the torque exhibits quadratic rate- dependence and scales
as the rod's length to the 4th power. The torque has no dependence on either
depth or airflow at these higher rates. A model used to describe the stopping
force experienced by a projectile impacting a granular bed can be shown to
predict these behaviors for our system's geometry, indicating that the same
mechanics dictate both steady-state and transient drag forces in granular
systems, regardless of geometry or material properties of the grains.
