Scale effects on cavitation inception in submerged water jets: a new look

Abstract

The present work is an investigation into the scale effects on cavitation inception in submerged water jets. Three scale effects were studied: (i) jet size, (ii) jet velocity and (iii) the nuclei population as a function of dissolved air content in the jet. Holography and schlieren photography were utilized to observe the flow. The results obtained in the present work were then used to illustrate the importance of previously overlooked flow variables in scaling cavitation inception data. An interesting finding of the present investigation was that the cavities at inception did not occur in the cores of the large vortex structures within the shear layer of the jets, as is commonly believed. A new parameter called the ‘probable cavitation occurrence’ parameter is also introduced in this paper. This parameter incorporates the effects of the nuclei number-density function and peak pressure fluctuations and it shows great promise in scaling cavitation-inception data.