What Causes the Water Droplet Tower Effect?

[ChrisHarvey]

I was just wondering if anyone could explain the phenomenon seen when a water droplet falls into larger expanse of water (i.e. the kind of water 'tower', like in the picture)?

It's something I've wondered about for a while, and I've never managed to come up with a satisfactory answer myself. What's more, it's a common front cover for fluid dynamics textbooks, yet it never seems to be explained!

Thanks,
Chris

 

[ChrisHarvey]

I was thinking along the lines of the kinetic energy of the falling droplet being converted into the potential energy of water in the 'tower', before being oscillating backwards and forwards between potental and kinetic energy of the ripples / waves. However, this doesn't seem to explain everything to me. Why do you often see separation in the 'tower' (near the top), with sometimes several drops of water?

 

[russ_watters]

If there is enough energy in the initial collision, the rebound has enough energy to send a droplet back up.

 

[matthew baird]

When the droplet hits the surface it displaces water right? so after that energy has dispersed, water fills back in the space and creates this tower effect..Same thing when you do a cannonball into the pool haha..