Reynolds_number

plasmapy.formulary.Reynolds_number(rho: Unit(‘kg / m3’), U: Unit(‘m / s’), L: Unit(‘m’), mu: Unit(‘kg / (m s)’))

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