Bubbles interactions in fluidized granular medium for the van der Waals hydrodynamic regime Adel M. Morad, Ehab S. Selima and Ahmed K. Abu-Nab Eur. Phys. J. Plus, 136 3 (2021) 306 Published online: 11 March 2021 DOI: 10.1140/epjp/s13360-021-01277-3