Grashof number

The Grashof number is a dimensionless number which approximates the ratio of buoyancy force to the viscous force acting on a fluid.

Gr = ( g β (T_s - T_inf) L³ ) / ν²

g gravity

β volumetric thermal expansion coefficient

T_s source temperature

T_inf quiescent temperature

L characteristic length

ν kinematic viscosity

See also Reynolds number, fluid dynamics, buoyancy.