Characteristics of aerodynamics for an automobile by fluid-structure coupled method

The traditional CFD simulation method generally only considers the effect of wind load on the aerodynamic performance of the automobile and neglects the influence of the coupling between the vibration of the body structure and the airflow, resulting in some discrepancies between the calculated results and the real car driving conditions. Taking the 1/4 standard MIRA model as the research object, the fluid-structure interaction effect is introduced into the numerical simulation through the bidirectional explicit fluid-solid coupling simulation method, and the aerodynamic forces, surface pressures, vibration frequencies and body attitude angles under different conditions are obtained. The differences between the current simulation results and the traditional simulation methods are analyzed. The accuracy of the current simulation results is verified by the wind tunnel test. Comparing with and without coupling simulation, the experimental results show that the coupling simulation is more consistent with the experimental results and the deviation of the data is within 5%, which verifies the accuracy of the coupled simulation method. The fluid-solid coupling effect is more affected with the increase in vehicle speed, especially the impact of aerodynamic lift directly affects the vehicle handling stability. As a result, the effect of fluid-solid interaction cannot be ignored at high speeds. © 2019, Jilin University Press. All right reserved.