Numerical investigation of the cavitating flow structure with special emphasis on the vortex identification method

Abstract

The three kinds of vortex identification methods, namely, [Formula: see text] criterion, [Formula: see text] criterion and [Formula: see text] method, are then employed to investigate the physical interactions between the cavitation and vortex dynamics around two-dimensional Clark-Y hydrofoil. The results show that compared to the [Formula: see text] and [Formula: see text] criterion, the [Formula: see text] method can capture the vortex structures with both strong and weak vortices, especially for the weak vortices located in the boundary of the cavity and the back region of the re-entrant flow. A proper value of [Formula: see text] in [Formula: see text] method based on the previous studies is then suggested to avoid the pseudo-vortex structure in cavitating flow field due to division by zero. The modified [Formula: see text] method with a proper [Formula: see text] is then applied to analyze the details of vortical structures in the growth of attached cavity, the re-entrant flow development stage and the cloud cavity shedding stage. The results show that the vortical structures are captured in the boundary and rear region of the attached cavity, the intensity and complexity of strong vortices in the rear boundary region of re-entrant flow increased with its development, and the strength and area of vortical structures at the trailing edge of hydrofoil increased with propulsion of cloud cavity before it sheds completely.