How to Tame a Free Non-Laminar Savart Sheet into Individual Jets?

In this article, we study the division of a non-laminar Savart sheet into individual jets by mean of local disturbances. We paint a precise portrait of a free non-laminar Savart sheet formed by the vertical impact of a jet on a horizontal disk, its evolution in the air and its break up.We then generate local disturbances, outside of the disk circumference, triggered by N radial triangular prisms placed directly in the non-laminar sheet. We show that, under given flow conditions and geometrical parameters for the triangular prisms, the sheet splits into individual jets. Depending on the incoming flow rate Q and on the geometry of the prism, the number of jets n can be either stable (and equal to N jets) or variable due to elastic coalescing of neighboring jets. Phase diagrams (Q, n) are obtained from experimental measurements for different geometrical parameters of triangular prisms. A semi-empirical model, which explains the generation of individual jets, is established. Finally, we characterize the droplets emitted from the non-laminar Savart sheet and from the jets in terms of diameters.