Flux

A flux records transport of a quantity through a surface per unit time. A flux density

j

gives total transport rate

\int_{S} j \cdot n d S

, where

n

is the unit normal vector. A conservation law relates its divergence to the local change in the quantity's density.

Table of contents
- Fick's laws Flux
- Diffusive flux Flux

Fick's laws

Fick's laws describe transport down a concentration gradient and the resulting change of concentration with time. Combining Fick's first law with a conservation law gives the diffusion equation.

Diffusive flux ( $j = - D \nabla u$ )

A diffusive flux transports a density

u

down its gradient according to Fick's first law. For scalar diffusion coefficient

D > 0

,

j = - D \nabla u

and the conservation law

u_{t} + div j = 0

gives a diffusion equation. If

D

depends on

u

, this becomes a nonlinear diffusion equation.

 Ancestors (4)

 Incoming links (212)

 View article source

 Discussion (0) New discussion

There are no discussions about this article yet.

 Articles by others on the same topic (1)

Flux by

Wikipedia Bot  1

Flux can refer to several different concepts depending on the context. Here are some of the most common interpretations: 1. **Physics and Engineering**: In physics, "flux" often refers to the rate of flow of a physical quantity through a surface. For instance, electromagnetic flux refers to the amount of electromagnetic field passing through a given area, while magnetic flux refers to the amount of magnetic field.

 Read the full article

  See all articles in the same topic Create my own version