  This paper examines the properties of flows around objects embedded within
common envelopes in the simplified context of a "wind tunnel." We establish
characteristic relationships between key common envelope flow parameters like
the Mach number and density scale height. Our wind tunnel is a
three-dimensional, cartesian geometry hydrodynamic simulation setup that
includes the gravity of the primary and secondary stars and allows us to study
the coefficients of drag and accretion experienced by the embedded object.
Accretion and drag lead to a transformation of an embedded object and its orbit
during a common envelope phase. We present two suites of simulations spanning a
range of density gradients and Mach numbers -- relevant for flow near the limb
of a stellar envelope to the deep interior. In one suite, we adopt an ideal gas
adiabatic exponent of $\gamma=5/3$, in the other, $\gamma=4/3$. We find that
coefficients of drag rise in flows with steeper density gradients and that
coefficients of drag and accretion are consistently higher in the more
compressible, $\gamma=4/3$ flow. We illustrate the impact of these newly
derived coefficients by integrating the inspiral of a secondary object through
the envelopes of $3M_\odot$ ($\gamma\approx5/3$) and $80M_\odot$
($\gamma\approx4/3$) giants. In these examples, we find a relatively rapid
initial inspiral because, near the stellar limb, dynamical friction drag is
generated mainly from dense gas focussed from deeper within the primary-star's
envelope. This rapid initial inspiral timescale carries potential implications
for the timescale of transients from early common envelope interaction.
