Radial flow cavitation between two overlying plates with varying gap: experiments and modeling.

Understanding the underlying cavitation physics in thin-layer radial flow geometries is primarily motivated by the need to prevent premature degradation of the flow surface geometry associated with cavitation damage. In this study, we conducted a comprehensive experimental investigation of the cavitation behavior of distilled water within a thin radial flow layer confined between two plates. This involves a lower circular plate with a centrally located fluid injection port and a matching plate resting on top of the lower plate. We analyzed both the steady and unsteady features of the resulting disk-shaped cavitation cloud, which abruptly collapses at a certain radial distance. In particular, the collapse distance of the cavitation disk and the unsteady oscillations of the cavitation disk cloud are documented for different inlet-outlet pressure ratios and for a varying gap between the plates. In our modeling efforts, we extend the model proposed in Phys. Fluids 35, 023302 to predict the radial location of cavitation bubble collapse as a function of gap thickness. The model predictions of the radial location of bubble collapse and are shown to be in excellent agreement with the experimental data. This approach will be valuable for predicting cavitation in complex internal flow system geometries.