  NGC 3115 is known as the low-luminosity active galactic nucleus which hosts
the nearest ($z\sim0.002$) billion solar mass supermassive black hole
($\sim1.5\times10^9~M_\odot$). Its Bondi radius $r_\mathrm{B}$ ($\sim3\farcs6$)
can be readily resolved with Chandra, which offers us an excellent opportunity
to investigate the accretion flow onto a supermassive black hole. In this
paper, we perform two-dimensional hydrodynamical numerical simulations,
tailored for NGC 3115, on the mass flow across the Bondi radius. Our best
fittings for the density and temperature agree well with the observations of
the hot interstellar medium in the centre of NGC 3115. We find that the flow
properties are solely determined by the local galaxy properties in the galaxy
centre: (1) stellar winds (including supernova ejecta) supply the mass and
energy sources for the accreting gas; (2) similar to the one-dimensional
calculations, a stagnation radius $r_\mathrm{st}\sim0.1~r_\mathrm{B}$ is also
found in the two-dimensional simulations, which divides the mass flow into an
inflow-outflow structure; (3) the radiatively inefficient accretion flow theory
applies well inside the stagnation radius, where the gravity is dominated by
the supermassive black hole and the gas is supported by rotation; (4) beyond
the stagnation radius, the stellar gravity dominates the spherical-like fluid
dynamics and causes the transition from a steep density profile outside to a
flat density profile inside the Bondi radius.
