RANS/LES investigation on the performance of air film fusion around a vertically launched underwater vehicle

Abstract

The Improved Delayed Detached Eddy Simulation (IDDES) model, energy equation, Volume of Fluid (VOF), and overlapping grid technique are adopted in this paper. Analyzing the performance of Froude numbers, and row-spacing-to-diameter ratios on the air film development process. The evolution of air film around a vertically launched underwater vehicle technology is the passive exhaust process, in which a high-pressure cavity of the limited volume is formed by crossflow shearing, environmental depressurization, and other factors. With the increase of the Froude number, the maximum diameter and length of the air film at the same feature position are increased, which is beneficial to air film fusion to a certain extent. However, research results indicate air film fusion does not occur at the large Froude numbers. In the establishment of the air film fusion model, there is a non-linear relationship between the Froude number and the pressure ratio inside and outside the cavity. As the Froude number increases, the pressure ratio becomes larger. However, the largest cross-sectional area of air film is not the largest. In the larger range of Froude numbers, the relationship between gas film fusion characteristics and Froude number is more complicated, and further research is studied. Finally, the effects of row-spacing-to-diameter ratios on the air film development process were discussed.