  We study the relativistic Bondi-Hoyle-Lyttleton accretion onto a
Schwarzschild black hole (BH), which is surrounded by rigid and small, randomly
distributed, bodies. These bodies are idealized representations of substructure
like stars passing close to the BH, bubbles created by stellar winds or cold
clumps.We explore cases where the filling factor of these bodies is small. The
flow is assumed to be adiabatic and move supersonically towards the black hole.
The interaction with these rigid obstacles transforms ram pressure of the flow
into thermal pressure through bow shocks, slowing down the flow and making the
accreting gas turbulent. As a consequence, although the flow reaches a
statistically-steady state, the accretion rate presents some variability. For a
flow Mach number at infinity of 4, a few of these objects (5 - 10) are enough
to increase the accretion rate about 50% over the accretion rate without
bodies, even though the gas is adiabatic and the filling factor of the
obstacles is small.
