What does the coefficient of discharge (C) represent in flow calculations?

The coefficient of discharge (C) specifically measures the effectiveness of a nozzle or orifice in discharging fluid. It represents the ratio of the actual flow rate to the ideal or theoretical flow rate that would be expected based on the area of the opening and the pressure driving the flow. This coefficient takes into account factors such as viscosity, turbulence, and the geometry of the nozzle, which can affect flow rates. Understanding the coefficient of discharge is crucial for engineers and operators, as it helps in accurately predicting the behavior of fluids in various systems, particularly in applications involving nozzles where precise flow control is necessary.

The other choices do not accurately describe the role of the coefficient of discharge. The flow passage area relates to the size of the opening but does not consider the factors influencing flow efficiency. The efficiency of the pipe pertains to how well it reduces friction losses but does not directly define how effectively a fluid exits a nozzle or orifice. Pressure loss in the system is a separate calculation that focuses on the energy loss due to friction and other factors along the flow path, rather than on how fluid is discharged through an opening.