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Dimensionless quantity
| (1) | \mbox{Ri} = \frac{\rm Gr}{ {\rm Re}^2} |
where
\rm Gr | Grashof number |
|---|---|
\rm Re | Reynolds number |
It is characterising the balance between Natural Thermal Convection and Forced Thermal Convection:
| (2) | \begin{cases} \mbox{Ri} \gg 1 & \mbox{forced convection may be ignored} \\ \\ \mbox{Ri} \approx 1 & \mbox{combined forced and free convection} \\ \\ \mbox{Ri} \ll 1 & \mbox{ free convection may be neglected} \end{cases} |
See also