Two-dimensional Modelling of Partial Cavitation with BEM. Analysis of Several Models

The present paper deals with the modelling of steady 2D partial cavitation on hydrofoils using a Boundary Element Method (BEM). An extensive analysis is carried out for several models, a non-linear model with the boundary conditions applied on the true cavity surface and a partially non-linear model with the boundary conditions applied on the foil surface beneath the cavity. For this second model two variants are considered, one with re-gridding at each iteration step and one without re-gridding. For the non-linear model both a re-entrant jet closure model and a pressure recovery model are implemented. Tests were devised to analyze the relevant features of the cavitation phenomenon obtained with the various models. Numerical studies on the convergence behavior, robustness and CPU time are presented, as well as comparisons between the models for different foils and loading conditions. The results for the re-entrant jet model are compared with other results available in literature. Finally, a quality assessment is proposed.