  We report here results of high-resolution hydrodynamical simulations of gas
flows in barred galaxies, with a focus on gas dynamics in the central
kiloparsec. In a single bar with an Inner Lindblad Resonance, we find either
near-circular motion of gas in the nuclear ring, or a spiral shock extending
towards the galaxy center, depending on the sound speed in the gas. From a
simple model of a dynamically-possible doubly barred galaxy with resonant
coupling, we infer that the secondary bar is likely to end well inside its
corotation. Such a bar cannot create shocks in the gas flow, and therefore will
not reveal itself in color maps through straight dust lanes: the gas flows
induced by it are different from those caused by the rapidly rotating main
bars. In particular, we find that secondary stellar bars are unlikely to
increase the mass inflow rate into the galactic nucleus.
