BERNOULLI’S LAW B026
A moving stream of liquid or gas exerts less sideways pressure than if it were at rest.
The result is that things seem to be drawn into the stream, but the higher pressure at the outside is really pushing them in.
This is the principle that causes a venturi to work.
Since there is a lot of fluid movement in an operating pump, we have to be concerned about the pressures being generated on the individual components.