Collapse of a long cylindrical bubble

The collapse of a cylindrical bubble was modeled using an approach similar to Rayleigh'solution for a spherical bubble. Rayleigh assumes an incompressible fluid, which, in the cylindrical case, leads to the problem of the fluid having infinite kinetic energy. To overcome the difficulty a “semi‐compressible” assumption is used, in which only the fluid contained in the acoustic envelope defined by r = ct is considered in the solution; the fluid outside this envelope being neglected. The results obtained with this approach were compared with solutions computed from a model using a finite element method. As in Rayleigh's solution for the spherical bubble, the calculations of the collapse time for the cylindrical bubble showed very good agreement with the numerical solutions. The results obtained for the pressure generated by the collapse of the cavity provide a qualitative description of cavitation effects produced by jets from shaped changes.