NUMERICAL SIMULATION OF THE FLOW AROUND THE HULL OF AN AHMED CAR TYPE VEHICLE

Abstract

Real currents around transport vehicles are turbulent. Calculation of such currents remains one of the most difficult problems. Today, there are no universal mathematical models of turbulence in computational aerodynamics. Reliable prediction of the characteristics of turbulent flows, refers to an extremely important scientific problem and is associated with the complexity and lack of study of turbulence as a physical phenomenon. The task of mathematical modeling of the aerodynamics of a ground vehicle is considered. The objective is to build a mathematical model, numerical method, solution algorithm and software to study the aerodynamic characteristics of a land vehicle of a poorly streamlined body type. The Reynolds averaged Navier-Stokes equations are used to describe the flow around the vehicle. To close the Reynolds averaged Navier-Stokes equations, the two-parameter SST Menter turbulence model is used. The SST model is superior to a number of other turbulence models, but in terms of computational simplicity and cost, it is inferior to single-equation models. A methodology, solution algorithm, and software have been developed. The finite-volume method was used for numerical integration of the system of differential equations. The problem was solved in multiblock formulation. The developed method was tested on standard problems of aerodynamics. A numerical simulation of the flow around the Ahmend Car ground vehicle model has been performed. All calculations were performed for Reynolds number Re=1.5*106. The influence of the inclination angle of the stern part of the vehicle model on the flow pattern was investigated. The studies have shown that the value of the angle of inclination of the stern significantly changes its aerodynamic characteristics. Further analysis of theoretical and practical research shows that the aerodynamic characteristics have a significant impact on the dynamics of ground vehicle movement. Thus, it is necessary to take into account the aerodynamic characteristics of a high-speed land vehicle in order to provide the necessary motion dynamics parameters.