Grashof number, gas to duct

Symbol
$\mathrm{Gr}_{gd}$
Formulae
$\frac{\beta_{gas} \delta _{d}^{4} g \left(- \theta_{air} + \theta_{e}\right)}{L_{d} \nu_{gas}^{2}}$Riser open at both ends
$\frac{D_{di}^{4} \beta_{gas} g \left(- \theta_{di} + \theta_{gas}\right)}{16 L_{d} \nu_{gas}^{2}}$Riser open at top and closed at bottom
$\nu_{gas}$
$\theta_{air}$
$\theta_{gas}$
Used in
$\mathrm{Nu}_{gd}$
$\mathrm{Ra}_{gas}$