A fuel spray induced vortex ring

It is demonstrated that a typical gasoline fuel injection process can be accompanied by the development of a fountain structure consisting of a spray jet and a vortex ring. In the case of a typical injection process lasting 3 ms, the vortex-like structures were observed starting t≈2 ms after the start of injection and lasting until about t=4.5 ms. The vortex ring moved in the direction of the jet and its distance from the axis of the spray increased with time. The axial spray velocity initially increased with increasing distance from the axis, then subsequently decreased. The observed velocity of the vortex ring and the proportionality of its radius and axial displacement are shown to be consistent with the concept of a time dependent turbulent eddy viscosity.