\begin{table}%t2
%\centering
\par
%\setlength{\tabcolsep}{2pt}
  \caption{Flame propagation velocities in the cellular regime. \label{vel_tab}}
    $$
    \begin{array}{lp{0.3\linewidth}p{0.35\linewidth}}
      \hline\hline
      \noalign{\smallskip}
      \mbox{$\rho_{\rm u}$ [$~{\rm g} ~{\rm cm}^{-3}$]} & \mbox{$v_{\rm cell} / s_{\rm l}$} (measured) &
      \mbox{$v_{\rm cell} / s_{\rm l}$} (according to Eq.~(\ref{vel_inc_eq}))\\
      \noalign{\smallskip}
      \hline
      \noalign{\smallskip}
      \mbox{2.5 $\hspace{0.5em}\times 10^7$} & 1.23 & 1.17 \\
      \mbox{5 $\hspace{1.2em}\times 10^7$} & 1.20 & 1.14 \\
      \mbox{7.5 $\hspace{0.5em}\times 10^7$} & 1.25 & 1.13 \\
      \mbox{1 $\hspace{1.28em}\times 10^8$} & 1.30 & 1.11 \\
      \mbox{1.25 $\hspace{0.01em} \times 10^8$} & 1.35 & 1.10 \\
      \mbox{1 $\hspace{1.28em}\times 10^9$} & 1.09 & 1.04 \\
      \noalign{\smallskip}
      \hline
    \end{array}
  $$
\end{table}