How does it work?

[Philo]

My neighbor has a Barracuda G3 pool vacuum.
I can't seem to figure out how the thing pulses which, I assume causes it to move around the pool.
Anyone know the principle of it?
Thanks

 

[mas985]

It is the diaphragm that opens and closes which creates the pulsating movement.

When closed it reduces the flow rate but increases the pressure on the diaphragm which then opens. Once opened, the pressure drops and closes again. This is repeated over and over again.