Calculate the ratio of actual to theoretical flow rate for an orifice or nozzle.
Flow Parameters
Calculation Results
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About this calculator
Overview
In fluid dynamics, the coefficient of discharge (Cd) accounts for losses due to friction and the contraction of the fluid stream (vena contracta) as it passes through an opening.
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Pro Tips
Cd is always less than 1.0 (typically 0.6 to 0.65 for sharp-edged orifices).
Theoretical flow is calculated using Torricelli's Law: Qt = A × √(2gh).
Using a rounded or bell-mouthed inlet can increase Cd to nearly 1.0.
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Fun Facts
"The term 'Vena Contracta' describes the point where the fluid stream's diameter is at its minimum."
"Flow meters like Orifice Plates and Venturi Meters rely heavily on known Cd values for accuracy."
"Cd consists of two parts: the coefficient of velocity (Cv) and the coefficient of contraction (Cc)."
