  We present a Direct Numerical Simulation (DNS) study of buoyancy-driven
bubbly flows in the presence of large scale driving that generates turbulence.
On increasing the turbulence intensity: (a) the bubble trajectories become more
curved, and (b) the average rise velocity of the bubbles decreases. We find
that the energy spectrum of the flow shows a pseudo-turbulence scaling for
length scales smaller than the bubble diameter and a Kolmogorov scaling for
scales larger than the bubble diameter. We conduct a scale-by-scale energy
budget analysis to understand the scaling behaviour observed in the spectrum.
Although our bubbles are weakly buoyant, the statistical properties of our DNS
are consistent with the experiments that investigate turbulence modulation by
air bubbles in water.

Fluid Dynamics