In what unit is the velocity of fluid most commonly stated?

The velocity of fluid is most commonly stated in feet per second (FPS) because this unit is widely used in engineering and scientific contexts, particularly in applications involving fluid dynamics. Measuring velocity in FPS allows for precise calculations and is consistent with the units typically used in the imperial system, especially in the United States. This unit provides a clear understanding of the speed at which a fluid moves, which is essential for design calculations and analyses in various engineering fields such as hydraulics and fluid mechanics.

Other units, like miles per hour or liters per minute, are less suitable for expressing fluid velocity directly. Miles per hour is generally used for vehicles and not for measuring the movement of fluids in processes. Liters per minute is a measure of flow rate, not velocity, as it quantifies the volume of fluid passing through a point per minute rather than the speed of the fluid itself. Centimeters per second is more common in scientific contexts but is not as prevalent in engineering practice in the U.S., where FPS is favored for clarity and relevance in fluid dynamics.