Describing material media


The material media are described by material regions :

  • mainly volume regions in 3D, possibly surface regions and line regions
  • mainly surface regions in 2D, possibly line regions

For additional information about regions, see chapter Physics: principles.

Material regions

Material regions (volume, face or line) enable the modeling of the material media. The physical properties of a medium are the same as the properties of the material associated with the corresponding region.

A region… enables the modeling…

conducting (+ heat source q )

of a conducting medium * (thermal conductivity k volumetric heat capacity ρCP)

with possibly a heat source (= thermal power), (uniform or space dependent)

* Concerning the properties of the conducting medium:

  • for a Steady state Thermal application: only the thermal conductivity k is necessary

  • for a Transient Thermal application: the thermal conductivity k and the volumetric heat capacity ρCP are necessary

Thin regions (3D)

In 3D, thin regions enable the modeling of conducting regions in which one dimension is much smaller than the other two.

The direction of the thermal flux in such regions can be selected by the user, as indicated in the table below.

Thin region Direction of the thermal flux
no restriction quasi tangential


(+ heat source q)

thin regions with random k conductivity

thin region with: k2 >> k1

Filiform regions

Filiform regions enable the modeling of conducting regions in which two dimensions are much smaller than the third one (e.g., small cross-section regions).

In 3D, the direction of the thermal flux is imposed by Flux. The thermal flux is usually considered tangent to the line that models the filiform region.