The Bernoulli’s theorem, named after the Swiss mathematician Daniel Bernoulli, is a fundamental principle in fluid dynamics. It describes the behaviour of an ideal fluid flowing in a streamline motion. It states that in a steady, incompressible flow of a fluid with no viscosity (or negligible viscosity), the total mechanical energy per unit mass along a streamline remains constant.

Mathematically, the Bernoulli’s theorem can be expressed as:

P+1/2 Pv2+pgh=Constant

The theorem suggests that at different points along a streamline, the sum of pressure, kinetic, and potential energy per unit mass of the fluid remains constant. So, if the fluid speeds up (velocity increases), the pressure it exerts decreases, or vice versa.


The Bernoulli Principle is based on the conservation of energy within a flowing ideal fluid. It is derived from the principle of conservation of energy. This principle states that in a closed system, energy can neither be created nor destroyed; it can only change forms.

In fluid dynamics, the Bernoulli Principle is an expression of this conservation of energy applied to a streamline flow of an ideal fluid. It describes how the total mechanical energy per unit mass of the fluid remains constant along a streamline.

The principle is built on the idea that in a steady flow with no friction (or negligible friction) and no significant losses, the total energy per unit mass of the fluid remains constant. When the fluid flows through different sections of a streamline, the sum of these energies remains the same. It means if one form of energy (like kinetic energy) increases, another form (like pressure energy) might decrease to maintain this constant total energy.

The Bernoulli Principle helps us to understand lots of things about how fluids move. It explains why planes can fly, how water moves in pipes. It is also useful in understanding how blood moves in our bodies.

It is a fundamental concept in fluid mechanics that helps to explain and predict the behaviour of fluids in motion.


The complete derivation of Bernoulli’s equation involves applying the conservation of energy to fluid flow along a streamline. Let us derive Bernoulli’s equation step by step:

Consider a fluid flowing steadily along a streamline.

In any two points along the streamline, the fluid’s total mechanical energy per unit mass (E) is equal to the sum of its kinetic, potential, and pressure energy per unit mass, remains constant.


The Bernoulli Equation, derived from the principle of conservation of energy applied to ideal fluid flow. It elucidates the relationship between pressure, velocity, and energy in a fluid along a streamline. This equation is foundational in fluid dynamics. It helps in the understanding and analysis of fluid behaviour in various engineering and scientific applications.


The Bernoulli Principle has a wide range of practical applications in various fields due to its ability to explain the behaviour of fluids in motion. Here are four notable applications:

Aerodynamics and Lift: The Bernoulli Principle plays a big role in how airplanes stay up in the sky. When air moves over an airplane wing, it speeds up. According to Bernoulli’s principle, fast moving air has lower pressure. So, the air above the wing has less pressure than the air below it. This pressure difference pushes the wing upward, helping the plane to fly.

Venturi Effect in Fluid Flow: The Venturi effect is based on the Bernoulli Principle. It describes the phenomenon where the velocity of a fluid increases as it passes through a constricted section of a pipe or tube. This increase in velocity is accompanied by a decrease in pressure perpendicular to the flow. The principle is used in devices like carburettors, atomizers, and flow meters.

Blood Flow in the Human Body: The Bernoulli Principle helps to explain blood flow within the circulatory system. The diameter of arteries and veins can affect the velocity and pressure of blood. Narrowing of blood vessels can increase blood velocity, reducing pressure (as per Bernoulli’s equation). Hence, it causes conditions like Stenosis and Aneurysms.

Sprayers and Atomizers: Devices like spray nozzles and atomizers use the Bernoulli Principle to convert liquid into a fine mist or spray. They work by making liquid go faster through a narrow space, which lowers the pressure. This makes the liquid break into tiny droplets. They are used in paint spraying, humidifiers, and fuel systems.

The Bernoulli Principle is not only a theoretical concept but also a practical tool. It is really helpful in applications like engineering, medicine, and flying planes. It helps us to figure out and control how fluids move for lots of different reasons.

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