  We investigate spectral properties of buoyancy driven bubbly flows. Using
high-resolution numerical simulations and phenomenology of homogeneous
turbulence, we identify the relevant energy transfer mechanisms. We find: (a)
At high enough Galilei number (ratio of the buoyancy to viscous forces) the
kinetic energy spectrum shows the Kolmogorov scaling with a power law exponent
$-5/3$ for the range of scales between the bubble diameter and the dissipation
scale ($\eta$). (b) For scales smaller than $\eta$, the physics of
pseudo-turbulence is recovered.
