### mixing length theory

**(mixing length model)**
(tractable simplified model of convection)

**Mixing length theory** (or **mixing length model**)
is a simplified model suitable for **convection** or turbulence
in fluids under gravity with pressure and temperature
gradients. Both those phenomena are chaotic so a
model that approximates their overall effect is
useful for incorporating in larger models, of
atmospheres, oceans, stellar structure, etc.

*Mixing length theory* takes the conditions that would make a
region of the fluid unstable (i.e., any small disturbance receives
positive feedback), works out the distance (the **mixing length**)
after which the fluid set in motion will reach a stable location,
and incorporating other factors, yields a resulting movement of
material and heat energy. Among the simplifications is that it
ignores (as mostly insignificant) some effects on the fluid-in-motion
by its surroundings.

(*theory,fluid dynamics,stellar structure*)
**Further reading:**

http://en.wikipedia.org/wiki/Mixing_length_model

**Referenced by pages:**

specific heat

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