# Rayleigh number gas/duct

Symbol
$\mathrm{Ra}_{gas}$
Formulae
 $\mathrm{Gr}_{og} \mathrm{Pr}_{gas}$ object to gas $\mathrm{Gr}_{gd} \mathrm{Pr}_{gas}$ gas to duct $\mathrm{Gr}_{da} \mathrm{Pr}_{gas}$ duct to ambient $\mathrm{Gr}_{od} \mathrm{Pr}_{gas}$ object to duct
Related
$\mathrm{Gr}_{da}$
$\mathrm{Gr}_{gd}$
$\mathrm{Pr}_{gas}$
Used in