When using a pitot tube to measure total pressure and static pressure in a duct, how do you find the velocity pressure?

In fluid dynamics, a pitot tube is utilized to measure pressure differences in a duct, which helps determine the velocity of the fluid. The total pressure measured by the pitot tube includes both the static pressure of the fluid and the dynamic component related to its velocity.

To find the velocity pressure, it is essential to isolate the dynamic pressure from the total pressure reading. This is accomplished by subtracting the static pressure from the total pressure. The resulting value, known as velocity pressure, directly relates to the kinetic energy of the moving fluid and is pivotal in calculating flow velocity through Bernoulli's equation or similar equations of motion.

The correct approach ensures that the measurement accurately reflects the energy associated with the fluid's movement, enabling the effective analysis and control of fluid systems within the context of instrumentation and controls.