# Grashof number, object to gas

Symbol
$\mathrm{Gr}_{og}$
Formulae
 $\frac{g \beta_{gas} {\delta_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser closed at both ends (Anders) $\frac{g \beta_{gas} {\delta_d}^4}{L_d {\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser open at both ends (Anders/Hartlein & Black) $\frac{g \beta_{gas} {L_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser open at top and closed at bottom (Anders) $\frac{g \beta_{gas} {L_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser closed at both ends (Hartlein & Black) $\frac{g \beta_{gas} {L_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser open at both ends, 133 ≤ $Ra$ ≤ 7000 (Hartlein & Black IIa) $\frac{g \beta_{gas} {L_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser open at both ends, $Ra$ > 7000 (Hartlein & Black IIb) $\frac{g \beta_{gas} {L_d}^3}{{\nu_{gas}}^2} \left(\theta_e-\theta_{film}\right)$ Riser open at top and closed at bottom (Hartlein & Black)
Related
$\beta_{gas}$
$\delta_d$
$L_d$
$\nu_{gas}$
$\theta_e$
$\theta_{film}$
Used in
$\mathrm{Ra}_{gas}$