Dynamics of a rising bubble impacting on the inclined wall with different angle and wettability*

In this study, we experimentally investigated the dynamics of a rising bubble (Reynolds numbers in the order of 10²-10³) impacting on the inclined wall, installed on top of the static water tank. While varying the material of the wall (e.g., PMMA and glass) and the inclination angle from 5° to 85°, we measured the bubble trajectory and shape deformation with high-speed photography and the liquid flow field with the two-phase particle image velocimetry. It is measured that the bubble either slides along the wall or perform repeated bouncing while rising, of which the transition is associated with both the inclination angle and wall boundary condition (i.e., wettability). By analyzing the bubble trajectory (such as the period and amplitude of the rebounds), and the spatio-temporal evolution of the flow field around the impacting bubble and the wall, we will further discuss the mechanism of the transition in the bubble dynamics.