6. Calculation of a flowmeter with depressurizing element

6.1 Software

Over the last century, numerous experimenters have measured the discharge coefficients C of various orifices. The data were first collected in tables, then smoothed out in the form of empirical relationships that could be processed by desktop numerical calculators, and more recently by microcomputers. These relationships are therefore evolving, and the formulation due to Stolz, used since 1980 for diaphragms, is tending to become obsolete in favor of the Reader/Harris-Gallagher equation, which in certain cases allows the lower limit of the aperture ratio to be significantly lowered.

The preliminary phase described in §