Jet formation in collapsing bubbles is ubiquitous whenever the setting is not spherically symmetric. For bubbles expanding and collapsing right at a flat solid boundary this asymmetry results from the viscous boundary layer that forms during the rapid expansion of the bubble. As a consequence, around maximum extension, the bubble shape deviates from a hemisphere. During collapse, flow focusing leads to cylindrically converging annular liquid inflow. For millimeter sized bubbles in water this annular inflow violently self-impacts at the axis of symmetry and leads to the formation of very fast thin axial jets [2,3,4,5]. The jet speed is of the order of 1000 m/s, exceeding the speed of the “standard” axial micro jets, that form by involution of the bubble wall, by an order of magnitude, see [1]. Since fast jet formation in this setting is causally related to the viscous boundary layer, it is of interest to vary the parameters that determine the thickness of the boundary layer and quantify their influence on the jet formation process. We present results from numerical simulations modeling the dynamics of single (laser-generated) cavitation bubbles in axial symmetry. The model consists of a bubble filled with a small amount of non-condensable gas in a compressible liquid. Expansion and collapse of the bubble are investigated by solving the Navier-Stokes equations discretized with the finite volume method. The volume of fluid method is used to capture the interface between liquid and gas. The model is implemented in the open source software package OpenFOAM [8]. Bubbles oscillating right at a solid boundary are considered. Bubble size, the viscosity of the liquid and the ambient pressure are varied. Configurations with high values of a bubble Weber number, Web = p∞ ℛeqmax/σ are considered, where p∞ denotes the ambient pressure, ℛeqmax the maximum bubble radius and σ the surface tension coefficient.