Method to calculate hydrodynamic force of ozzle

#METHOD TO CALCULATE HYDRODYNAMIC FORCE OF OZZLE FREE#

You have to agree that it is going faster at the tip than through the hose. The fact is, there has to be an N3 pair somewhere, to explain the acceleration of the water exiting the nozzle. The force is, of course, due to the water pressure but not just the static pressure. Those two quantities are not the same so they can't be equated like that. The only force that the fluid exerts on the nozzle body is pressure. But, as far as the nozzle body knows, it is only the fluid pressure that it feels. As long as the fluid pressure within the nozzle is higher than the pressure outside the nozzle, the axial force that the fluid exerts on the nozzle will be in the positive flow direction, irrespective of what is happening with the momentum exchanges of the fluid.Д¬ertainly the momentum increase affects the pressure of the fluid within the nozzle.

#METHOD TO CALCULATE HYDRODYNAMIC FORCE OF OZZLE FREE#

The momentum increase of the fluid affects the fluid pressure upstream within the nozzle, but, treating the nozzle as a free body, it is only the fluid pressure that determines the axial force on the nozzle (aside from the tension at the hose connection). On the way out of the nozzle, the velocity has increased and the mass flow rate is the same so doesn't that mean momentum has increased on the way through the nozzle? That argument sounds convincing until you consider the momentum transfer situation. So you could say that the fireman is needed in order to control any lateral force. If the hose and nozzle are totally aligned, the reaction force will be upstream, on the compressor only. If it is pointed at right angles to the hose then forces on the hose will cancel and all the reaction force will be on the nozzle. All that's necessary is to know the entry and exit diameters and the flow rate (and density of course).Д®dit: the direction of the nozzle will affect what actual force is acting on the nozzle. It is not necessary to consider the details of the passage of the water and the details of the pipe / nozzle to get a good, near enough answer. This is the same principle as a rocket or jet engine. That will require a constant reaction force on the hose to stop it moving backwards. If the nozzle is of smaller diameter than the hose (usual setup?) then the water will be accelerating as it goes through the taper and emerge at a higher speed than it had in the hose, which involves a forward force acting on the water as it flows through.

Method to calculate hydrodynamic force of ozzle