Pseudo-turbulence in two-dimensional buoyancy-driven bubbly flows: A DNS study Rashmi Ramadugu, Vikash Pandey and Prasad Perlekar Eur. Phys. J. E, 43 11 (2020) 73 Published online: 30 November 2020 DOI: 10.1140/epje/i2020-11997-0