Bernoulli's Principle

Bernoulli's principle is a fundamental physical principle that describes the relationship between fluid velocity and pressure. In this article, we will explore the basics of Bernoulli's principle and its various applications. You'll learn about the conservation of energy and the principle of continuity, and how these concepts underlie Bernoulli's principle. We'll also discuss some real-world examples of how Bernoulli's principle is used to explain the lift force that keeps airplanes in the air, the functioning of airfoils and hydrofoils, and the behavior of fluids in pipes and other enclosed systems. Whether you're a student, an engineer, or simply curious about the world around you, this article will provide you with a basic foundation in Bernoulli's principle.

Dec 31, 2022

4 min read

Bernoulli's principle is a physical principle that states that an increase in the velocity of a fluid (such as a gas or a liquid) is accompanied by a decrease in pressure. This principle is named after the Swiss mathematician and scientist Daniel Bernoulli, who first described it in the 18th century.

Bernoulli's principle is based on the conservation of energy and the principle of continuity, which states that the total amount of mass in a system remains constant. According to Bernoulli's principle, as a fluid flows through a constriction or a tube with a varying cross-sectional area, the velocity of the fluid increases in the narrow section and decreases in the wider section. This change in velocity is accompanied by a corresponding change in pressure, with the pressure decreasing in the narrow section and increasing in the wider section.

Bernoulli's principle has a wide range of applications in various fields, including aerodynamics, hydrodynamics, and engineering. It is used to explain the lift force that keeps an airplane in the air, the functioning of airfoils and hydrofoils, and the behavior of fluids in pipes and other enclosed systems. It is also used to predict the behavior of fluids under different conditions and to design devices that rely on fluid flow, such as pumps, compressors, and jet engines.

Real-world examples

Bernoulli's principle has a wide range of applications in various fields and has many real-life examples. Here are a few examples of how Bernoulli's principle is used in everyday life:

1. Airplanes: Bernoulli's principle explains the lift force that keeps an airplane in the air. As an airplane flies through the air, the shape of its wings causes the air to flow faster over the top of the wing and slower under the wing. According to Bernoulli's principle, this difference in air velocity results in a difference in pressure, with the pressure under the wing being higher than the pressure over the wing. This pressure difference creates an upward force on the wing, known as lift, which counteracts the weight of the airplane and allows it to stay airborne.

2. Fans: Fans use Bernoulli's principle to create airflow. When a fan blade rotates, it pushes air in the direction of the blade's motion. The air flows faster over the top of the blade and slower under the blade, creating a difference in pressure. This pressure difference results in a net force on the air, causing it to flow out of the fan.

3. Balloons: Bernoulli's principle explains why a balloon expands when you blow into it. When you blow into a balloon, you increase the velocity of the air inside the balloon. According to Bernoulli's principle, this increase in air velocity is accompanied by a decrease in pressure inside the balloon. The decrease in pressure causes the balloon to expand, as the air inside the balloon pushes outward against the walls of the balloon.

4. Water fountains: Water fountains use Bernoulli's principle to create the upward flow of water. When water flows through a narrow nozzle, it speeds up and its pressure decreases, according to Bernoulli's principle. This decrease in pressure causes the water to rise up and create the fountain effect.

5. Hydrofoils: Hydrofoils, such as water skis and surfboards, use Bernoulli's principle to achieve lift and stability in the water. The shape of the hydrofoil's surface causes the water to flow faster over the top of the foil and slower under the foil, creating a pressure difference that lifts the hydrofoil out of the water. This lift allows the hydrofoil to travel faster and more efficiently through the water.