Bernoulli’s principle is a fundamental concept in fluid dynamics stating that in a streamlined flow, the pressure within a fluid decreases as its velocity increases. This principle arises from the conservation of energy within the fluid.
When a fluid (like air or water) moves through a constricted or narrow region of a pipe, it speeds up to maintain the flow rate. Since the total mechanical energy (sum of pressure energy, kinetic energy, and potential energy) of the fluid remains constant, an increase in kinetic energy (due to increased speed) must be compensated by a decrease in pressure energy—resulting in lower pressure in faster-moving regions.
Examples:
- Airplane Wings: The curved top of the wing causes air to move faster over it, creating lower pressure above the wing and generating lift.
- Atomizers: When air is blown across a tube, the reduced pressure draws liquid upward and sprays it out.
- Venturi Effect: Fluids passing through a narrow section of a pipe accelerate, reducing pressure in that section—used in carburetors and fluid measurement devices.
Bernoulli’s principle helps explain many everyday phenomena and is crucial in engineering and aerodynamics.