# Reynolds number for air

The Reynolds number is a dimensionless number.

Symbol
$\mathrm{Re}_{air}$
Formulae
 $\frac{V_{air} D_o}{\nu_{air}}$ for cable $\frac{V_{air} Di_t}{\nu_{air}}$ for tunnel $\frac{V_{air} D_o}{\nu_{air}}$ in free air $\frac{V_{air} D_{do}}{\nu_{gas}}$ for riser
Related
$D_{do}$
$D_o$
$Di_t$
$\nu_{air}$
$\nu_{gas}$
$V_{air}$
Used in
$\mathrm{Nu}_{da}$
$T_{at}$
$T_{sa}$