Originally Posted by jwalker
Funny you should say that cos I was reading the Rolls Royce website last night to try and get more understanding and they used that as an example but it brings us back to exactly the situation in the two wee diagrams I drew. Closed container, then open at one end.
Great minds, eh?
I am not sure WHY it works either. Just trying to get my head around it too.
Firstly, thanks to DJL.
I am starting to think along the lines of Force = Mass x Velocity with Newtons 3rd. I dont think it has anything to do with any of the pressure laws.
You have a given Mass (the water sucked up) you Accelerate it with the impellor and nozzle which increases the Force applied. Apply Newtons 3rd and you have a reaction force in opposition and equal to the ejected Mass.
The force is transfered to the boat via the jet assembly because the impellor will not let the water return from whence it came.
I seems to have nothing to do with system pressure after all. In a baloon the force is applied the elastic nature of the baloon its self, not the pressure stored in it. (I think)