  Vortex shedding is an oscillating flow that is commonly observed in fluids
due to the presence of a blunt body in a flowing medium. Numerical simulations
have shown that the phenomenon of vortex shedding could also develop in the
magnetohydrodynamic (MHD) domain. The dimensionless Strouhal number, the ratio
of the blunt body diameter to the product of the period of vortex shedding and
the speed of a flowing medium, is a robust indicator for vortex shedding, and,
generally of the order of 0.2 for a wide range of Reynolds number. Using an
observation from the Atmospheric Imaging Assembly on board the Solar Dynamics
Observatory, we report a wavelike or oscillating plasma flow propagating upward
against the Sun's gravitational force. A newly formed shrinking loop in the
post-flare region possibly generates the oscillation of the upflow in the wake
of the hot and dense loop through vortex shedding. The computed Strouhal number
is consistent with the prediction from previous MHD simulations. Our
observation suggests the possibility of vortex shedding in the solar corona.
