Pipe flow, a branch of
hydraulics and
fluid mechanics, is a type of
liquid flow within a closed
conduit (conduit in the sense of a means of containment). The other type of flow within a conduit is
open channel flow. These two types of flow are similar in many ways, but differ in one important aspect. Pipe flow does not have a
free surface which is found in open-channel flow. Pipe flow, being confined within closed conduit, does not exert direct atmospheric pressure, but does exert hydraulic pressure on the conduit.