Bernoulli’s Equation (Continued)
p
A
Dx
Flow Work (p/r) :
It is the work required to move fluid across the control volume boundaries.
Consider a fluid element of cross-sectional area A with pressure p acting on the control surface as shown.
Due to the fluid pressure, the fluid element moves a distance Dx within time Dt.  Hence, the work done per unit time DW/Dt (flow power) is:
Flow work per unit mass
Flow work or Power
1/mass flow rate
Flow work is often also referred to as flow energy