use the values given in B13 for the available processed material and the core radius of a typical GC, respectively $1.3\times10^5\,{\mbox{$\mathrm{M}_{\odot}$}}$ and 1 parsec. The average density would then be around $2 \times 10^{-18} \,\mathrm{g\,cm^{-3}}$. However, the density will vary and can locally be higher. To provide a better comparison with M09, we adopt their assumed number density of $n = 5 \times 10^{6}\,\mathrm{cm^{-3}}$ and mean molecular weight $\mu=2.3$, which translates to a mass density, $\rho_{\rm ISM}$, of $1.92 \times 10^{-17} \,\mathrm{g\,cm^{-3}}$. In the case of GCs with multiple stellar populations, $\mu$ may be somewhat larger because the enriched populations exhibit a helium enhancement compared to primordial molecular clouds.

We assume an inflow velocity, $v_{\rm ISM}$, of 20 $\mathrm{km \ s}^{-1}$ in order to approximate the typical velocity dispersion in GCs. This means that our set-up is in the supersonic regime and the treatment of the artificial viscosity is important. We will discuss the artificial viscosity in Sec. \[sec:visc\_eda1\]. The high velocity gives a very small Bondi-Hoyle accretion radius, as we will discuss in Sec. \[sec:sink\_eda1\]. The inflow is modelled by adding a slice of ISM with thickness $v_{\rm ISM}dt$ at the inflow boundary and random uniformly distributing the SPH-particles 