# Diffusion Coefficient

Diffusion coefficient, abbreviated as D, also called diffusivity, expresses the transfer rate of a substance by random molecular motion.

## Diffusion Coefficient formula

\(\large{ D = \frac{ 1 }{ \mu } \; \sigma \; T_a }\) |

### Where:

Units |
English |
Metric |

\(\large{ D } \) = diffusion coefficient | \(\large{\frac{ft^2}{sec}}\) | \(\large{\frac{m^2}{s}}\) |

\(\large{ T_a }\) = absolute temperature | \(\large{F}\) | \(\large{K}\) |

\(\large{ \sigma }\) (Greek symbol sigma) = Stefan-Boltzmann constant | \(\large{constant}\) | |

\(\large{ \mu }\) (Greek symbol mu) = friction coefficient | \(\large{dimensionless}\) |

Tags: Coefficient Equations Soil Equations Diffusion Equations