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How does fluid velocity change with pipe diameter?

Fluid velocity is inversely proportional to pipe diameter, according to the principle of continuity.

This is because of the principle of continuity, which states that the mass flow rate of a fluid must remain constant as it flows through a pipe of varying diameter. This means that as the cross-sectional area of the pipe decreases, the fluid must flow faster to maintain the same mass flow rate. Conversely, as the cross-sectional area of the pipe increases, the fluid can flow more slowly while still maintaining the same mass flow rate.

Understanding the properties of fluids, including their density and how they react under different pressures, is crucial in analysing how these dynamics change in different environments.


This relationship between fluid velocity and pipe diameter is important in many applications, such as in the design of pipelines and pumps. For example, if a pipeline needs to transport a certain amount of fluid per unit time, the diameter of the pipe can be adjusted to achieve the desired flow rate without having to increase the velocity of the fluid to an impractical level.

It is also important to note that the viscosity of the fluid can also affect the relationship between fluid velocity and pipe diameter. In highly viscous fluids, the velocity may not increase as much as expected when the diameter of the pipe is reduced, due to the resistance of the fluid to flow.

Additional insights into how forces affect fluid behaviour can be gained by understanding the principle of moments and their impact on fluid dynamics.


Further exploration of work and energy in physical systems provides a broader context for understanding the energy requirements and efficiencies when managing fluid flows in various pipe diameters.

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