Torricelli Discharge Velocity
Torricelli Discharge Velocity
Fluid draining from a tank speeds up with the head above the opening. Torricelli’s law gives the ideal velocity.
From energy conservation v = √(2gh). where g is gravity and h the head of liquid above the opening.
Inputs
g := 9.81 m/s^2=9.81 m/s^2
h := 3 m=3 m
The pressure head converts entirely to velocity head.
v := sqrt(2·g·h)=7.67 m/s
Results
This is the same speed an object would reach falling from height h. Real jets are a little slower due to contraction and friction (a discharge coefficient near 0.6–0.98).
Assumptions & limitations
- Ideal, frictionless flow.
- Tank surface far larger than the opening.
- Atmospheric pressure on both surfaces.