In this work, direct numerical simulation of turbulence is coupled to lagrangian tracking to study the behavior of 220
m bubbles in a vertical turbulent channel flow. Both one-way and two-way coupling approaches and both upward and downward flows are considered. For each simulation, the same external imposed pressure gradient is considered. In one-way simulations, this leads to a shear Reynolds number of Re = 150. In the coupled cases, the presence of bubbles increase/decrease the driving pressure gradient, respectively in upward/downward flow, thus yielding to an increase/decrease of the wall shear stress and of the shear Reynold number. For the considered bubble average volume fraction (
= 104 ), the corresponding shear Reynolds number are about
= 174 for the upflow case and
= 121 for the downflow case. Statistics of the fluid and of the bubble phase are presented. The interactions between bubble and the near-wall turbulence structures is also investigated and a preferential bubble segregation in high-speed/low-speed zones is observed for the upflow/downflow cases respectively. An attempt to describe the transfer rate between the gas and the liquid will be included with some preliminary results.