Modeling Gaseous Cavity in Fluid Flow

Abstract

The paper considers the formation of a ventilated cavity in a flow of water behind a streamlined body. Numerical modeling of the two-phase flow is based on the Volume of Fluid (VOF) method. The system of equations for the water-air mixture consists of the Navier-Stokes equation, continuity equation, energy conservation equation, and diffusion equation, and the equations of state (ideal gas equation, Boussinesq approximation). This system is closed by the Smagorinsky model of turbulence (the model of large eddies). The geometry was designed in accordance with the experimental cavitator using the SALOME open package. The calculation mesh was built by the method of cutting out the geometry from the calculation domain and step-by-step densification near the streamlined body using the snappyHexMesh utility. The results of the simulation of the formation of the air cavity behind the disk cavitator are presented. The influence of the parameters such as air injection velocity, water flow velocity on the formation of the air cavity, its size and stability is illustrated. An approximation dependence is proposed that describes the main parameters of the system. Numerical simulation of the non-stationary problem of the two-phase flow of two compressible fluids without a phase change was done using the compressibleInterFoam numerical model of the open-source package OpenFOAM. The obtained results were analyzed and compared with experimental data. The perspectives of subsequent studies related to the development of a three-phase numerical model using open source packages of programs for accounting for natural cavitation are ilustrated.