re: Has anyone else here ever created Water Hammer?

If you've ever shut off a faucet, especially in the basement of an older house, and heard the pipes rattle or knock, that's the same phenomenon.

Fluid is traveling through a pipe. It has momentum. When a valve closes, the flow energy is converted to pressure. The pressure wave travels back upstream of the blockage at the wavespeed of sound in that fluid. That pressure wave exerts a force on the outside pipe walls. This can cause rupture if the pressure if the pressure exceeds the pipe limits. It happens at faulty welds.

It's a concern in any liquid pipeline regardless of fluid type. In large pump stations, it can knock pipes off of pipe racks if the system was designed poorly.