The "Reynolds Number" (Re) is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.
Applicable units are those of quantitykind:ReynoldsNumber
http://en.wikipedia.org/wiki/Reynolds_number
http://dbpedia.org/resource/Reynolds_number
The "Reynolds Number" (Re) is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.
$Re = \frac{\rho uL}{\mu} = \frac{uL}{\nu}$, where $\rho$ is mass density, $u$ is speed, $L$ is length, $\mu$ is dynamic viscosity, and $\nu$ is kinematic viscosity.
http://www.iso.org/iso/catalogue_detail?csnumber=31896