What is the definition of "actual pressure" in fluid dynamics?

In fluid dynamics, "actual pressure" refers to the pressure exerted by a fluid in a confined space, which is closely associated with the concept of total pressure in a contained fluid. The correct understanding of "actual pressure" emphasizes the pressure within a closed or confined environment, such as a pipe or tank, where the fluid is not allowed to exit into an ambient atmosphere.

While flow rates in closed systems are an important aspect of fluid dynamics, they specifically refer to the volume of fluid moving through a system per unit time, rather than the concept of pressure itself. Actual pressure is not measured by flow rates but is rather a measure of how much force exerted by the fluid acts on the walls of its container.

When considering pressure differences, such as between various points in a fluid system, this pertains more to concepts like gauge pressure or differential pressure rather than the total or actual pressure experienced by the fluid itself. Therefore, focusing on the definition of actual pressure means understanding it in terms of the overall force exerted on a specific area within a fluid system, which is fundamentally tied to the dynamics of fluids in contained environments.