The Paradox of the Vena Contracta

Abstract

The preponderance of evidence, both theoretical and experimental, appears to show that the vena contracta does not occur at the same location as the minimum pressure point in the Reynolds number range greater than 10,000. Fortunately, however, this result has little effect on the measurement engineer in the field. All of the coefficients for vena contracta taps remain valid except that they should probably be referred to as “minimum pressure point taps” unless someone can provide a simpler description.