PITOT TUBE

An instrument used to measure the velocity of flowing water, with the velocity head of the stream an index of velocity. It consists essentially of an orifice held to a point upstream in the water, connected with a tube in which the rise of water due to velocity head may be observed and measured. It also may be constructed with an upstream and downstream orifice, with two water columns, in which case the difference in height of the water columns in the tubes is the index of velocity.