Analysis/Discussion and Results

From this first set we gather that when the bullet hits, there is a round spray on the entry side, and a spray on the exit side, both of which disperse. There appears to be a hole or column where the bullet hits the water, which contracts into a single fine spray over time. To further investigate the shape of the spray, we make the angle between the camera and the water wall smaller in the following sets of data.


The instant before the pellet hits. It looks as if the surface of the water is already reacting (possibly because of air disturbance)	Just as the pellet hits the water wall there appears to form an initial spray from the contact surfaces between the pellet and water.	As the pellet enters the thin film of water, initial splash is growing and a column of air seems to form in the wake of the pellet.	This column is very visible now as the pellet is further along, but has not exited the water yet.	The initial splash is becoming more dispersed and a small ring appears to form at the entry point of the pellet

As the pellet exits the water, the ring becomes more apparent. We believes this happens because as the pellet exits the water, the column of air is collapsing.	As the pellet moves further away from the wall, you notice that is still pulling water behind it. Also, the column continues to collapse. You can see how the once concentric splash is now narrowing into a column of water.	The entry column is continuing to collapse.	The column is almost completely collapsed. The exit spray once dispersing is now converging behind the pellet.	The pellet still has not separated from the exit splash and the entry column appears to be almost collapsed. Unexpectedly, it appears to collapse started at the back and continuing forward.

The pellet has finally separated form the exit splash and the entry column is pretty much completely collapsed, but the water filling it is still swirling.	This is very far along (the pellet is way out of the frame). The exit splash has dispersed, but the column of water caused by the collapsing entry column is still very visible. The entry column is completely collapsed, but the swirling water is still visible inside the water.

From the second set of data we gathered that the spray on the entry side of the wall is a thin film at first, then contracts to form a tight single spray. The hole in the water wall is indeed an air column, and contracts over time with the formation of the entry-side spray. The exit-side spray is pulled along by the bullet and disperses over time. The next set of data will gather information on the phenomenon viewed from the exit-side.

The exit-side spray, investigated in this set of data, appears to be water pulled along by the bullet. Visible spray must not be going as fast as the bullet because over time it lags behind the bullet. The air column is again clearly visible and directly related to the collapse of the entry side spray. It appears that when the entry-side spray collapses, so does the exit-side spray. The final image shows that there are two tight sprays in either direction of the collapsing hole shortly before the water wall entirely resumes its flow.


Just as the pellet hits the water wall there appears to form an initial spray from the contact surfaces between the pellet and water.	Sometime after the pellet has left the water wall, the wall still has a puncture and this appears to close and form a jet.	This jet appears to fan out into a spray.	The jet appears to fan out even further into a roughly circular larger spray.	The spray continues to grow in size.	The spray appears mostly diffused, as though a thick small ring had been stretched out until it was fairly thin.


Just as the pellet hits the water wall there appears to form an initial spray from the contact surfaces between the pellet and water. The rays visible around it are the splash on the bullet entry side, viewed through the rippling water.	As the pellet enters the thin film of water, initial splash is growing and a small circular hole seems to form in the wake of the pellet. The ripple disturbance to the upper left is simply an air bubble.	This circular hole is very visible now as the pellet is further along. The spray from where the bullet initially hit, visible through the water, appears to be spreading.	The exiting bullet pulls the splash along behind it. The hole from the bullet's path begins to contract.

The exiting bullet continues to pull the splash along behind it. The hole from the bullet's path contracts a little more.	The exiting bullet continues to pull the splash along behind it. The air column is collapsing further.	The water pulled by the bullet is dispersing some, and the air column is contracting further.	Now we see the air column is closing more quickly and the spray dispersing further. The spray from the bullet's entrance seems to be contracting into one dark mass of water. The rays going out from the column are most likely the splash on the other side, viewed through the rippling of the water.

The spray from the bullet's entry continues to contract into a tight splash, whereas the spray from the bullet's exit continues to disperse.	The spray from the bullet's entry appears nearly fully contracted as it is clear the column of air made by the bullet is closing.	The spray from the bullet's entry is now one fine line. The bullet has pulled and dispersed the water.	The bullet is no longer visible, but the contraction of the air column is almost complete.