Air injection as a tool for reducing frictional drag in liquid transport systems has a rich history, particularly in applications such as pipelines and ship surfaces. Among these air injections, millimeter bubbles stand out due to their paradoxical ability to both reduce and amplify drag. The mechanisms underpinning these dual effects remain enigmatic, especially since visualizing the micro-scale film flow between bubbles and wall surfaces using Particle Image Velocimetry (PIV) is challenging. To unravel these mysteries, we used OpenFOAM on the Fugaku supercomputer for high-fidelity simulations. These simulations examined the bubbles' formation stages and interactions, such as coalescence, break-up, and the intricate micro-scale film flows between bubbles and wall surfaces, paving the way for a more comprehensive understanding of their role in fluid dynamics.