Numerical simulation of the layer mixing problem based on a new two-fluid turbulence model

Abstract

A layer of mixing flows is formed between parallel flows, which is an important fundamental problem in turbulent flows. The problem is related to many industrial applications and natural phenomena, such as air spraying in fuel injection systems and wave destruction in the ocean. The velocity is stripped between gas and liquid flows, causing interfacial instability, which can be convective or absolute, depending on the flow properties and injection parameters. In this study, the mixing of two flows with different velocities is simulated. The calculations are based on the numerical solution of a system of non-stationary equations using a new two-fluid turbulence model. The results of the longitudinal velocity and turbulent stress profiles in various sections of the channel are obtained. The control volume method was used for the difference approximation of the initial equations, and the relationship between velocities and pressure was found using the SIMPLE procedure. In this case, the viscous terms were approximated by the central difference, and for the convective terms, the second-order accuracy scheme of A. A. Samarsky was used. To confirm the correctness of the numerical results, a comparison is made with experimental data from the NASA database. The known results of the SA and SST models are also presented. Despite the use of a coarse grid for numerical calculation, it is shown that the accuracy of the results obtained based on a new two-fluid turbulence model is not worse than the results obtained using RANS models for predicting mixed flows in a flat channel.