# Jetting Effect

The jetting effect is modeled as an overpressure applied to each element of the airbag (Figure 1).

$$\text{\Delta}{P}_{jet}=\text{\Delta}{P}_{1}\left(t\right).\text{\Delta}{P}_{2}\left(\theta \right).\text{\Delta}{P}_{3}\left(\delta \right).\mathrm{max}\left(\overrightarrow{n}.{\overrightarrow{n}}_{1},0\right)$$

with:

- ${\overrightarrow{n}}_{1}$
- Being the normalized vector between the projection of the center of the element upon segment ( ${N}_{1}$ , ${N}_{3}$ ) and the center of element as shown in Figure 1.
- $\theta $
- The angle between the vector ${\overrightarrow{MN}}_{2}$ and the vector ${\overrightarrow{n}}_{1}$ .
- $\delta $
- The distance between the center of the element and its projection of a point upon segment ( ${N}_{1}$ , ${N}_{3}$ ).

The projection upon the segment (
${N}_{1}$
,
${N}_{3}$
) is defined as the projection of the point in direction
${\overrightarrow{MN}}_{2}$
upon the line (
${N}_{1}$
,
${N}_{3}$
) if it lies inside the segment (
${N}_{1}$
,
${N}_{3}$
). If this is not the case, the projection of the point upon
segment (
${N}_{1}$
,
${N}_{3}$
) is defined as the closest node
${N}_{1}$
or
${N}_{3}$
. If
${N}_{3}$
coincides to
${N}_{1}$
, the dihedral shape of the jet is reduced to a conical
shape.