Summary

1 A 1 v1 = 2 A 2 v2

For many situations -- for most situations involving a liquid but not a gas -- we can assume the density does not change. This is called an incompressible fluid. For those cases,

A 1 v1 = A 2 v2

(1/2) v2 + P + g y = constant

or

(1/2) 1 v12 + P1 + 1 g y1 = (1/2) 2 v22 + P2 + 2 g y2

If the vertical height y does not change, this means

(1/2) v2 + P = constant

or

(1/2) 1 v12 + P1 = (1/2) 2 v22 + P2

Applications

Homework
Return to ToC, Fluids in Motion
(c) 2002, Doug Davis; all rights reserved