Hagen number

The Hagen number is a dimensionless number used in forced flow calculations. It is the forced flow equivalent of the Grashof number

It is defined as:

$Hg = \frac{-d p}{\rho d x}\frac{L^3}{\nu^2}$

where:

$\frac{-d p}{d x}$ is the pressure gradient; for natural convection:=(gρβΔT) i. e. Hg -> Gr

L is a characteristic length

$ρ$ is the fluid density

$ν$ is the kinematic viscosity

See also: Hagen number, Density, Dimensionless number, Grashof number, Kinematic viscosity