Cavitation and Nuclei

Contrary to the general impression, water and other common liquids, when pure, have high tensile strength. Cavitation would be impossible at the highest velocities currently encountered. In practice all liquids appear to cavitate as soon as the pressure tends to drop below the vapor pressure, thus implying that liquids have no tensile strength. This discrepancy is explained by the presence of "weak spots" whose characteristics have as yet only been inferred. This paper presents the results of an experimental investigation of the weak spots present in ordinary water. The results are consistent with the model of the nucleus proposed by Harvey, but are apparently inconsistent with other models currently found in the literature. After summarizing the results of the experimental program, the paper concludes with a series of implications concerning the engineering significance of the nuclei in industrial liquids