Get Your Head Around Velocity Head

摘要

BERNOULI'S THEOREM is one of the most used equations in fluid engineering. The theorem expresses conservation of energy in a flow system by relating velocity, pressure and elevation. Its basic form is for an incompressible fluid with inviscid flow:1/2(v~2/g) + (p/ρ) + z = c where v is velocity, g is acceleration due to gravity, p is pressure at the location, p is fluid density, z is elevation above a reference plane and c is a constant in a unit of length. The term 1/2(v~2/g) commonly is referred to as the velocity head and has units of height of the flowing fluid. It can be thought of as the amount of potential energy required to accelerate a fluid to its actual flowing velocity. It also is the amount of head generated when fluid velocity drops to zero.