Bernoulli's Equation

Bernoulli's equation states that for an ideal fluid flowing steadily along a streamline, the total mechanical energy per unit volume stays constant: pressure energy, kinetic energy, and gravitational potential energy can convert into one another. It follows from conservation of energy applied to a small fluid element, assuming the fluid is incompressible, non-viscous, and there is no pump, turbine, or major frictional loss. In practice, a rise in speed usually comes with a drop in pressure or a change in height, because the fluid’s energy is being redistributed rather than created or destroyed.

Use this when analysing smooth, steady flow in pipes, nozzles, tanks, vents, and open-channel situations where friction and compressibility can be neglected. It is especially useful for relating pressure differences to flow speed or elevation changes in hydraulics and aerodynamics.

• Forgetting that the equation applies along a streamline and for steady, ideal flow, not arbitrary turbulent flow everywhere
• Mixing units or using density in g/cm^3 without converting to kg/m^3
• Ignoring the height term when the points are at different elevations