Snapshot of five different simulations, taken at the same simulation time. The 2D simulations are in polar coordinates; the radial coordinate is in 10¹¹ cm units; and the angular coordinates are in degrees. The color-coding denotes the vorticity of the fluid flow The simulation domains are rotated to fit on the figure. Left panel: Models v036_6_150x20 (top), v036_9_150x30 (middle), and v036_12_150x40 (bottom). These models have different angle widths, but the same resolution. Right panel: v036_6_150x20 (top), v036_6_150x30 (middle), v036_6_150x40 (bottom). These models have the same angle width, but different horizontal resolutions. In the left panel we can see that with increasing opening angle, the number of structures is also increasing in the HI region (at around 3.4 × 10¹¹ cm radius.). In the HeII zone (at around 3.2 × 10¹¹ cm), the size of the vortices increase. This means that the initial model with of 6° degrees used by Geroux & Deupree (2013) is inadequate to properly capture the properties of the flow structure in this area. Meanwhile, we can see on the right-hand side that the number of structures in the HI region is similar with higher resolutions (although more details appear). An animated version of this figure is available online.