The dimensionless Grashof number, Gr, is a combination of density , viscosity , temperature difference T, length scale L, the acceleration of gravity g, and

The dimensionless Grashof number, Gr, is a combination of density ρ, viscosity μ, temperature difference ΔT, length scale L, the acceleration of gravity g, and the coefficient of volume expansion β, defined as β = (−1/ρ) (∂ρ/∂T)p. If Gr contains both g and β in the numerator, what is its proper form?