 ## What is Bernoulli’s theorem and conservation of energy?

Last updated on April 3rd, 2023 at 11:17 am

Definition: In fluid dynamics, Bernoulli’s theorem states that the total energy of moving fluid consisting of the gravitational potential energy of the elevation, the energy associated with the fluid pressure and the kinetic energy of the moving fluid is constant. In simple terms, it is the relation between pressure, velocity and elevation of moving fluid.

Conservation of energy states that energy can neither be created nor be destroyed, it can only be converted from one form to another form of energy.

## What are the applications of Bernoulli’s equation?

### 1. Venturimeter

A venturi meter measures the flow of fluid in a pipe that has a non-uniform cross-section..  Venturimeter works on the principle of Bernoulli’s theorem. When fluid passes through the inlet and gets to the constricted section of the pipe, it creates a pressure difference in both sections due to the increase in velocity of the fluid. Two pressure gauges are connected in both sections and the flow rate can be calculated by taking the difference between pressures at both sections.

### 2. Water sprayer

When you press the piston in a water sprayer, it forces the air to rush out of the horizontal tube, causing a decrease in pressure at P2, which is lower than the pressure at P1. This lower pressure at P2 causes water to be drawn in from the vertical tube that is connected to the container. It breaks up into fine spray along with the air and flows out of the nozzle.

### 3. Lifting of an aircraft 