\begin{table}%t2 \caption{\label{modtab}Some properties of the two and three-dimensional simulations: number of grid points in $r$ ($N_{r}$), $\theta$ ($N_{\theta}$) and, $\phi$~($N_{\phi}$)~direction, spatial resolution in~$r$ ($\Delta r$ in~10$^{6}$~cm), $\theta$~($\Delta \theta$), and $\phi$~($\Delta \phi$)~direction, characteristic velocity~$v_{\rm c}$ (in 10$^{6}\cms$) of the flow, expansion velocity at temperature maximum~$v_{\rm exp}$ (in~$\cms$), typical convective turnover timescale~$\tau_{\rm cnv}$ (in~s) and maximum evolutionary time~$t_{\rm max}$ (in~s), respectively.} %\centering \small \begin{tabular}{p{1.cm}|p{2.cm}p{0.7cm}p{0.7cm}p{0.7cm} p{0.7cm}p{0.7cm}p{0.7cm}p{1.1cm}} \hline \hline run & grid & $\Delta r$ & $\Delta\theta$ & $\Delta\phi$ & $v_{\rm c}$ & $v_{\rm exp}$ & $\tau_{\rm cnv}$ & $t_{\rm max}$ \\ \hline hefl.2d.a & $180\times90$ & 5.55 & 1.33\degr & -- & $1.44$ & 24. & 650 & 9500\\ hefl.2d.b & $360\times240$ & 2.77 & 0.75\degr & -- & $1.84$ & 92. & 510 & 130~000\\ hefl.3d & $180\times90\times90$ & 5.55 & 1.33\degr & 1.33\degr & $0.85$ & 10. & 1105 & 6000\\ \hline \end{tabular} \end{table}