Effect of active flow control on flow characteristics and drag of Ahmed body under crosswind conditions

Abstract

This study investigates the effects of different flow control strategies on the drag and rear flow characteristics of a simplified Ahmed model (φ = 35°) under crosswind conditions, with the yaw angle ranging from 0° to 8°. The results show that the yaw angle negatively affects the drag regardless of whether control is applied, and applying control can mitigate this effect to some extent. When the yaw angle is less than 2°, the drag reduction effect of active flow control remains almost constant; however, as the yaw angle increases further, the drag reduction effect begins to decrease significantly. Among the three control strategies, the strategy targeting longitudinal vortices (CCV) is most sensitive to crosswind, with the drag reduction effect diminishing the fastest, while the strategy targeting recirculation bubbles (Rec) is the least sensitive, with the drag reduction effect declining the slowest. Based on the pressure measurements at the rear of the model, the reduction in drag is most noticeably reflected on the vertical rear face of the model, and the changes in airflow around the slanted rear surface of the vehicle are the primary factors influencing the model’s aerodynamic performance.