Influence of the near wall treatment on the flow features around a two-dimensional hydrofoil close to the free surface

摘要

This work was performed in the framework of a numerical study aiming at modeling the ventilation phenomenon, which has been recognized to be important for marine screws, rudders and submerged hydrofoils (see experiments by Nishiyama, 1961; Shiba, 1953; Koushan, 2006). The present analysis focuses on the validation and verification of the solver adopted in the case of a two-dimensional hydrofoil close to the free surface. This problem has caught much attention after the experiments carried out by Duncan (1983), who observed breaking and non-breaking waves over a hydrofoil model and measured the free-surface profile. Several authors have attempted to reproduce Duncan's experiments using different numerical approaches. Among them, the inviscid BEMs by Landrini et al. (1999) and Faltinsen and Semenov (2008) have reproduced accurately the experimental results until breaking occurs. The following flow evolution can not be handled by potential flow solvers. RANS simulations capture the correct form of the wave and are intrinsically able to handle breaking waves, but tend to under-predict the wave amplitude. Some authors have better captured spilling breakers (Rhee and Stern, 2002; Muscari and Di Mascio, 2003) implementing a breaking-wave model based on empirical data (Cointe and Tulin, 1994).