# Numerical Simulation of Cavitation Erosion Aggressiveness Induced by Unsteady Cloud Cavitation
## 3 Results
### Influence of Cavitation Model  
Figure 9 demonstrates that the contours of \(\overline{p}\) obtained with the different cavitation models are similar, which reinforces the assumption that the study of the influence of the cavitation model on \(P_{den}\) and \(P_{load}\) can be done using \(\overline{p}\) as driving pressure. Figure 10 presents the contours of condensation \(\dot{m}\) and \(P_{den}\) at different instants of the shedding process obtained with the [PERSON], Sauer and Kunz cavitation models, as well as the evolution of \(P_{load}\) on the hydrofoil surface along the chord. Figure 8: The accumulated total power load during the second shedding cycle predicted using \(p(t)\) or \(\overline{p}\) with different cavitation models. Figure 9: Contours of \(\overline{p}\) predicted with the different cavitation models. In Figure 10, the Zwart model predicts a cloud cavity at instant 1.3 with low condensation rate on its outer region and a maximum \(P_{load}\) of about 60 kWm\({}^{-2}\) which is the lowest figure compared to the other models. On the contrary, the Sauer and the Kunz models predict a smaller cavity volume and a higher \(P_{load}\) induced by the higher condensation rate on the outer region of the cloud. More specifically, the Kunz model predicts the highest \(P_{load}\) of about 240 kW m\({}^{-2}\) at 40% of the chord because a part of the condensation region of the cloud cavity is much closer to the hydrofoil surface than in the rest of results. Similarly, the Zwart model predicts again the smallest condensation rate and \(P_{load}\) at instant 1.4. The other two models predict a relatively higher intensity especially for the Kunz one. At instant 1.5, the cloud cavity still presents a large volume with the Zwart model, meanwhile with the [PERSON] model the cavity already vanishes at instant 1.44, as shown in Figure 6, and it reappears with a very small volume due to the collapse rebound. With the Kunz model, the cloud cavity finishes its final collapse at this particular instant. This indicates that the final collapse occurs at different instants and at different chord locations depending on the cavitation model. Furthermore, the collapse process predicted with the Zwart model creates a lower \(P_{load}\) than the rest. Comparing Figures 6 and 10, it can be seen that the [PERSON] model predicts a much higher condensation rate than with the [PERSON] model when the final collapse occurs, which leads to a higher \(P_{den}\) and \(P_{load}\), as shown in Figure 7.  
Figure 10: Results obtained with the Zwart **(left)**, [PERSON] **(middle)** and [PERSON] **(right)** models at different instants comprising contours of \(\dot{m}\) from vapor to water **(top)** and of \(P_{den}\), and value of \(P_{load}\) on the surface along the chord (red line in bottom graphs). Black isolines of \(a_{v}=0.1\) show the location of the main vapor cavities at each instant. Figure 11 shows the results at instant 0.5 corresponding to an analogous situation to the one observed at instant 1.5 presented in Figure 9(c). By comparing these results, it can be seen that the cavity behavior differs between the two consequent cycles depending on the cavitation model being used. The cavity topologies at these two instants are very similar with the Sauer model, showing that the sheet cavity has reached its maximum length with a high \(P_{load}\) at its closure region and that a very small cloud cavity appears at 70% of the chord inducing a small \(P_{load}\). Likewise, the cavity behavior and the \(P_{load}\) provided by the Zwart model at these two instants are also similar. However, the results for the Kunz model are different since there is a cloud with a larger volume of vapor that induces the maximum \(P_{load}\) at 75% of the chord at instant 0.5, which cannot be observed at instant 1.5 in Figure 9(c). Similarly, the space-time distributions of \(P_{load}\) in Figure 5 are significantly different between the time span from 0 to 1 and from 1 to 2 for the [PERSON] model, meanwhile they are quite similar for the other two models.