Thermal diffusivity

The thermal diffusivity represents the speed of penetration and attenuation of a thermal wave in a medium. Thermal diffusivity is often indicated by the letter has, D or the Greek letter $\backslash \; alpha$ (Alpha).

$D\; =\; \{\backslash \; lambda\; \backslash \; over\; \backslash \; rho\; C\}$ (in m ² /s).

$\backslash \; lambda$ is the thermal Conductivité material (in)

$\backslash \; rho$ is the Density material (in)

$c$ is the Specific heat material (in)

Physically, thermal diffusivity is the capacity of a material to impose its Température on the external medium. This size is strongly related to the thermal Effusivité. For example, a metal chair and a Tabouret wood in a part are exactly at the same temperature (that of the part). However the chair appears colder than the stool. That is explained by the fact that the diffusivity of metal is higher than that of wood, thus the transfers of heats are carried out more quickly. Our body loses more quickly of heat what gives this feeling of cold.

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