Flux

Flux is defined as released energy per area-unit per time-unit. Flux can be used to model electrical heating mats or solar radiation. In case of solar radiation, the flux is depending on the position of the sun during the day.

The flux is acting on the surface of the structure.

If a shield or a convective transmission coefficient (representing a shield) is defined, the flux is released below the protection. This makes sense when the flux is arising from electrical heating mats.

If the flux is arising from solar radiation, no shield or convective transmission coefficient (representing a shield) can be present. A convective transmission coefficient representing the thin layer of air, alternatively a wind model, is accepted, because the solar radiation looks through the air layer. If an insulation is still to be included together with solar radiation, it must be modelled as a (thin) volume.