What does the diameter mentioned in velocity calculations refer to?

In velocity calculations, the diameter that is referred to typically represents the inside diameter of the pipe. This is because the inside diameter directly affects the flow rate and velocity of water moving through the pipe. The velocity of the fluid is calculated based on the cross-sectional area of the pipe, which is derived from the inside diameter. Utilizing the inside diameter accounts for the effective space through which the fluid flows, ensuring accurate calculations regarding flow characteristics.

For instance, if the outside diameter were to be considered, it would not properly represent the volume of fluid moving through the pipe, as it would include the pipe material itself and not just the space available for liquid movement. Similarly, an average diameter across fittings would not provide a consistent measurement for flow throughout the entire system, as these fittings may vary in size. The diameter related to the water source could potentially refer to an entirely different measurement and would not pertain to the specific calculations made within the context of the piping system. Thus, focusing on the inside diameter is essential for accurate fluid dynamics assessments in landscape architecture contexts.