Study on the interaction between the bubble and free surface close to a rigid wall

Abstract

A numerical model considering the bubble, rigid wall and free surface is established by using the boundary element method (BEM). We concentrate on the influence between a bubble and the free surface near a rigid wall with 30 degrees to the vertical plane. We conduct this study from two aspects. First, to study the effect of the bubble position, a dimensionless distance parameter is delimited: γh denoting the distance between the initial bubble and the vertical plane crossing with the free surface and the rigid wall. We find that for large-scale bubbles, two liquid jets form at the collapsing stage of the bubble, and a change in the height of the free surface is found to rely on γh. At small γh the free surface reaches its peak height on the rigid wall, while the peak occurs above the bubble at relatively large γh. Second, we simulate the behavior of the bubble and free surface under different bubble scales, and we find that the effect of bubble scale on the free surface is mainly reflected in the height of the free surface above the bubble; this height increases continuously when the effect of the bubble scale is relatively great, whereas increases first and then decreases when the effect of the bubble scale is relatively small.