Torricelli's law of efflux

Torricelli's law of efflux

[¦tȯr·ə¦chel·ēz ′lȯ əv ′ē‚fləks]
(fluid mechanics)
The velocity of efflux of liquid from an orifice in a container is equal to that which would be attained by a body falling freely from rest at the free surface of the liquid to the orifice.