Reynolds_number

plasmapy.formulary.dimensionless.Reynolds_number(rho: Unit("kg / m3"), U: Unit("m / s"), L: Unit("m"), mu: Unit("kg / (m s)")) -> Unit(dimensionless)

The Reynolds Number is a dimensionless quantity that is used to predict flow patterns in fluids. The Reynolds Number is defined as the ratio of inertial forces to viscous forces. A low Reynolds Number describes smooth, laminar flow while a high Reynolds Number describes rough, turbulent flow.

\[Re = \frac{\rho U L }{\mu}\]

Aliases: Re_

Parameters:
  • rho (Quantity) – The density of the plasma.
  • U (Quantity) – The flow velocity of the plasma.
  • L (Quantity) – The characteristic length scale.
  • mu (Quantity) – The dynamic viscosity of the plasma.
Warns:

~astropy.units.UnitsWarning – If units are not provided, SI units are assumed.

Raises:

Examples

>>> import astropy.units as u
>>> rho = 1000 * u.kg / u.m ** 3
>>> U = 10 * u.m / u.s
>>> L = 1 * u.m
>>> mu = 8.9e-4 * u.kg / (u.m * u.s)
>>> Reynolds_number(rho, U, L, mu)
<Quantity 11235955.05617978>
>>> rho = 1490 * u.kg / u.m ** 3
>>> U = 0.1 * u.m / u.s
>>> L = 0.05 * u.m
>>> mu = 10 * u.kg / (u.m * u.s)
>>> Reynolds_number(rho, U, L, mu)
<Quantity 0.745>
Returns:Re – Dimensionless quantity.
Return type:Quantity