Minor losses in fluid flow are primarily caused by which of the following?

Minor losses in fluid flow are primarily associated with energy losses that occur due to discrete events in the flow path, such as changes in direction, area, or states within the system. These changes often manifest at fittings like valves, tees, and elbows, where the flow experiences abrupt changes that disrupt its smooth trajectory, leading to turbulence and energy dissipation.

The energy losses caused by these fittings are categorized as "minor losses," despite potentially having significant impacts on the system’s overall energy budget. This distinguishes them from "major losses," which are attributed to friction along extended lengths of piping. By quantifying and accounting for these minor losses, engineers can better predict the total head loss in fluid systems and design more efficient systems.

Other options may refer to factors affecting fluid dynamics but do not specifically target the behaviors that are classified as minor losses. For instance, acceleration in flow rate pertains to changes in velocity rather than discrete components in the flow path, while expansion of fluid temperature relates to thermal dynamics rather than the frictional losses caused by fittings. Gravity's influence on fluid flow is a factor in energy equations, but it plays a different role compared to the localized energy losses from fittings and is not categorized under minor losses in the same context.