{latex}
\large
$$
D_{FcmTubeMax}  = \left( {{{L_{FcmTubeMax} \left( {128Nu_{FcmAlum} Q_{FcmMaxLa\min ar} } \right)} \over {\pi gHL_{FcmTube} }}} \right)^{{1 \over 4}}
$$

{latex}