\large
$$
V_{max}  = G_{max} ^{{\raise0.7ex\hbox{$2$} \!\mathord{\left/
 {\vphantom {2 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}}  \cdot \left( {{{2 \cdot \nu  \cdot b} \over {k_b  + f \cdot {b \over {4 \cdot R_h }}}}} \right)^{{\raise0.7ex\hbox{$1$} \!\mathord{\left/
 {\vphantom {1 3}}\right.\kern-\nulldelimiterspace}
\!\lower0.7ex\hbox{$3$}}} 
$$