Grashof Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Grashof number, abbreviated as Gr, a dimensionless number, is the ratio of buoyant to viscous forces.

 

Formulas that use Grashof Number

\(\large{ Gr = \frac { g \; l^3 \; \alpha_c \; \left( T_s - T_{\infty}  \right) }    {\nu^2} \; }\)  (for vertical flat places) 
\(\large{ Gr = \frac { g \; l^3 \; \alpha_c \; \left( T_s^{\nu^2} - T_{\infty}  \right) }    {\nu^2} \; }\)  (for bulk bodies and pipes)

Where:

\(\large{ Gr }\) = Grashof number

\(\large{ T_{\infty} }\) = bulk temperature

\(\large{ g }\) = gravitational acceleration

\(\large{ \nu }\)  (Greek symbol nu) = kinematic viscosity of fluid

\(\large{ l }\) = vertical length

\(\large{ T_s }\) = temperature of surface

\(\large{ \alpha_c }\)  (Greek symbol alpha) = thermal expansion coefficient of fluid

 

Tags: Equations for Heat Transfer Equations for Force