Applications of Bernoulli's equation

Even though Bernoulli's equation is only correct for hypothetical nonviscous fluids, it nevertheless has wide applicability. Many examples were discussed in class (with demos); here is a brief summary with references:

• The Pitot tube is used to measure air speed. See Tritton, page 420.

• The Venturi effect arises from the combination of the continuity equation and the Bernoulli equation when an incompressible fluid flows through a constriction in a pipe: the speed must be higher and the pressure drops. See Tipler, page 350, and Tritton, page 121, for applications.

• Atomizers and similar devices are described in Tipler, page 351, and How Things Work, page 174.

• Hurricanes and tornadoes have strong winds that can literally lift a roof off, by the Bernoulli effect.

• Flapping flags and the Kelvin-Helmholtz instability are treated by Tritton on page 262. It is important to realize that it is not enough to find a solution of the hydrodynamic equations: one must also check that the solution is stable.