  An expansion of cross-sectional area directly impacts the mass flow along a
coronal loop, and significantly alters the radiative and hydrodynamic evolution
of that loop as a result. Previous studies have found that an area expansion
from chromosphere to corona significantly lengthens the cooling time of the
corona, and appears to suppress draining from the corona. In this work, we
examine the fluid dynamics to understand how the mass flow rate, the energy
balance, and the cooling and draining timescales are affected by a non-uniform
area. We find that in loops with moderate or large expansion (cross-sectional
area expansion factors of 2, 3, 10, 30, 100 from photosphere to apex),
impulsive heating, for either direct thermal heating or electron beam heating,
induces a steady flow into the corona, so that the coronal density continues to
rise during the cooling phase, whereas a uniform loop drains during the cooling
phase. The induced upflow carries energy into the corona, balancing the losses
from thermal conduction, and continues until thermal conduction weakens enough
so that it can no longer support the radiative losses of the transition region
(TR). As a result, the plasma cools primarily radiatively until the onset of
catastrophic collapse. The speed and duration of the induced upflow both
increase in proportion to the rate of area expansion. We argue that
observations of blue-shifted spectral lines, therefore, could place a
constraint on a loop's area expansion.
