How slip length influences wall shear stress from jetting cavitation bubbles

Boundary slip can strongly influence the wall shear stress generated by a collapsing cavitation bubble near a solid surface. Here, we investigate this effect by systematically varying slip length l l l and bubble stand-off distance gamma γ γ . We show that boundary slip has negligible influence on bubble dynamics and jet formation prior to jet impact, but markedly alters the near-wall flow during jet spreading. Increasing l l l substantially reduces both outward and inward peak shear stresses, suppresses flow separation during fast jet spreading and reorganises the spatio-temporal stress distribution. We derive a scaling for the maximum outward stress tau Subscript m τ m τ ₘ with tau Subscript m Baseline almost equals mu upper U 0 upper R e Superscript 0.5 Baseline left parenthesis upper U Subscript e Baseline divided by upper U 0 right parenthesis Superscript 1.5 Baseline divided by left parenthesis 0.3 upper R Subscript italic max Baseline plus l left parenthesis upper U Subscript e Baseline upper R e divided by upper U 0 right parenthesis Superscript 0.5 Baseline right parenthesis τ m ≈ μ U 0 R e 0.5 ( U e / U 0 ) 1.5 / ( 0.3 R max + l ( U e R e / U 0 ) 0.5 </mml:mro