Surface of object

When several cables are present, the mutual radiant area between them must be subtracted from the area radiating to the riser inner surface.

Symbol
$A_{er}$
Unit
m$^2$
Formulae
$\pi D_o$single cable
$2\left(1-0.182\right) \pi D_o$two cables touching
$3\left(\pi-0.618\right) D_o$three cables touching trefoil