Numerical simulation of the flow in a flat suddenly expanding channel based on a two-fluid turbulence model

Abstract

The article presents the results of a numerical study of the flow structure in a flat channel in the zone of its sudden expansion in the form of a ledge. 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 profiles of longitudinal velocity and turbulent stress in different sections of the channel before and after the ledge, as well as the change in the coefficient of friction for the lower wall of the channel depending on the distance after the ledge are obtained. For the difference approximation of the initial equations, the control volume method was used, and the relationship between velocities and pressure was found using the SIMPLEC procedure. In this case, the viscous terms were approximated by the central difference, and for convective terms, a second-order scheme of accuracy against the flow was used. To confirm the correctness of the numerical results, a comparison was made with experimental data from the NASA database for the Reynolds number Re=36000. And the influence of the calculated grid in the results of the study was also investigated.