## 3 Results
### Impact of Short-Duration Water Jet
#### 3.2.1 Case J1  
In this case, the jet impact is the strongest of all the studied cases due to the highest impact velocity. The main features of the interaction are presented in Figure 5, the resolution  
Figure 4: Summary of data obtained for free-falling drop experiments listed in Table 2. Solid lines show the approximation found for Case D1 (see Figure 2). \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**Case**} & **Water Jet Diametere** & **Water Volume** & **Impact Velocity** & **Melt Temperature** & **Melt Depth** & **Maximum Melt Rise** & **Time of Maximum** \\  & **mm** & **mL** & **m/s** & **~C** & **mm** & **mm** * & **Rise, ms * \\ \hline J1 & 5.37 & 1 & 11 & 300 & 14 & \(>\)34; 30; 84 & \(>\)114; \(>\)151; 163 \\ J2 & 12.97 & 1 & 3 & 300 & 14 & 18.4 & 123 \\ J3 & 6.69 & 1 & 4 & 300 & 14 & 515; 38.2 & 156; 139 \\ J4 & 7.5 & 1 & 3.6 & 300 & 14 & 73; 49.7; 20.41 & 201; 168:161 \\ J5 & 6.22 & 1 & 3.1 & 300 & 14 & 53.4; 44 & 173; 152 \\ \hline \hline \end{tabular}  
* When the cumulative jet split into several parts, more than one value is given in relation to each melt part, from the upper to the lower one.
* Estimated from the camera field-of-view exit and re-entry times, assuming free motion in the gravity field.  
\end{table} 
Table 3: Parameters of impulse-jet impact experiments. of each frame is 800 \(\times\) 600 pixels, and the field of view dimensions are 60.8 \(\times\) 45.5 mm. The camera was placed at a distance of 25 cm from the impact point and its line of view was inclined at 15 degrees with respect to the liquid surface. Note that the water jet approaching the melt surface is not of simple geometry; it consists of a compact leading volume followed by a thinner tail, see Figure 5a. Accordingly, the crown formed due to the impact was asymmetric. Numerous melt droplets of 1-2 mm diameter was scattered by the splashing, thus detaching from the rising crown. In Figure 5b, the shape of the crown, as well as a few clearly visible melt drops are shown at the instant that the crown reached its maximum height. Unlike the weak disturbance caused by the free falling droplet, the perturbation of melt in this case was strong enough for the cumulative jet to appear as the result of cavity collapse. Moreover, the rising cumulative jet was fragmented into three distinct melt volumes. At 112.5 ms, a rather large drop-shaped volume detached from the leading edge of the rising jet, and it left the field of view by 114 ms. Then, another jet fragmentation occurred, with a melt volume that had an elongated shape with a longitudinal size of about 15 mm, which detached at 135 ms and disappeared from view at 151 ms. At 204 ms, the latter detached part of the jet returned to the camera field of view to impact the melt surface  
Figure 5: Melt–water jet interaction, Case J1: (**a**) pre-impact shape of water jet; (**b**) shape of the melt crown and droplets, t = 18 ms after the impact; (**c**) cumulative jet and droplet shedding; (**d**) visible shape of the primary cumulative jet at different times; (**e**) secondary cumulative jet at the instant of its maximum rise, t = 339 ms; (**f**) bubble floating on the melt surface. at 267 ms. At 333 ms, the first detached melt fragment re-entered the camera view to fall on the melt surface at 368 ms. In the experiment, the camera was placed quite close to the impact point (at a distance of 25 cm), so that its field of view was insufficiently wide to record the first and second detached melt volumes; these left the image upper boundary quite quickly. In Table 3, the rise in height for the first two parts is shown as \">32 mm\", which indicates the height of the upper boundary of the camera field of view. Also, the rising times of these two parts are shown as the times when they left the camera field of view.