# Distance of throw of water jets

#### mauro

I need to determine the distance of throw of a water jet in calm air(no wind).
Is there anyone who has the equation ready as to say the throw T as a function of nozzle diameter, water speed at nozzle outlet (or pressure at nozzle inlet) and angle of the nozzle?

Bye
Mauro

PS How the air slow down a water jet? In case of a slug fired from a gun resistance is 1/2 C(ro)V^2 where ro is air density.
It is common experience to see that water jet trajectory is not simmetrical. The ascending part is much longer than descending side. Since I need to determine the distance of throw for a given jet, simmetrical solutions brings to grossly overestimation of the result.
Is there anyone with field experience, as for example nozzle manufacturers for irrigation purposes, willing to help me?
Or on the contrary a physic amateur with a theoretical formula?

Thank you to you all

Mauro

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#### russ_watters

Mentor
If you have the exit speed and direction, its a simple Newtonian motion equation. You don't need anything else. You can also use pressure to calculate velocity if you need to.

#### bogdan

like a projectile with the speed of the water at the exit...nothing else...

#### Jonathan

I think it is
y=vTsin(&Theta;)-g(T^2)/2
x=vTcos(&Theta;)
with v=exit velocity, T=time,&Theta;=exit angle above horizontal, and g=9.8 m/s^2.

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