The Rayleigh prolongation factor at small bubble to wall stand-off distances

The Rayleigh collapse time is the it would take to shrink an empty spherical bubble in infinite liquid domain zero size, which a function of ambient pressure and initial radius. If solid boundary located vicinity shrinking or collapsing bubble, then flow hindered, such that prolonged. This can be quantified with prolongation factor $k$ . Here, we provide for intermediate smallest wall stand-off distances. It measured single laser-induced cavitation bubbles water close boundary. Maximum radii are determined from microscopic high-speed imaging at one million frames per second. Collapse times acoustically via acoustic transients emitted during seeding collapse. experimental findings compared, good agreement, numerical simulations based on volume fluid method. As result, polynomial fit versus distance given near-wall water. Then influence viscosity studied numerically regime.