In the present study collapse stage of cavitation bubbles in the vicinity of a rigid boundary in quiescent water has been studied numerically with concentrating on initial bubble radius and stand-off parameter (the ratio between the distance of bubble center and the wall, and maximum bubble radius γ). Navier-Stokes and energy equations in an axisymmetric domain were hired to simulate the flow, and VOF method was used in order to track the interface between liquid and gas phases. Surrounding liquid was assumed to be incompressible water, and water vapor as ideal gas was considered for the bubble contents. Simulations were done in a wide range of bubble radius and stand-off parameter. Good agreements with reference experimental data were achieved. Results show that for the same bubble radii maximum jet velocities increase and collapse time decreases with increasing stand-off. However, increasing initial bubble radius causes the differences between maximum jet velocities, bubble volume at the moment of jet impact to the other side of the bubble, and collapse time of the cases with different values of stand-off to decrease. For the bubbles with smaller values of stand-off liquid jet forms sooner and its length with respect to bubble size is greater. Also, for the same standoff parameters liquid jet is wider and its length with respect to bubble size is smaller for smaller bubbles. As bubble manner tends to spherical with increasing stand-off parameter, calculated velocities in present study become larger than those of physical values.

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