Impact of Water Jets

What is the impact of jets of water in hydraulic machines and fluid dynamics?

What force does a water jet imposes on different surfaces like plane surface, curved surface and moving curved vanes etc.
A theoretical model for the force necessary to hold the impact surface stationary is obtained by
applying the integral forms of the continuity and momentum equations. The details of the model
depend on whether or not the fluid stream leaving the impact surface is symmetric relative to the
vertical axis of the surface.