Numerical simulations on aerodynamic drag reduction of a 25° Ahmed body by jet flow

Abstract

In this work, for the aerodynamic characteristics of a 25° Ahmed body, I reduce its aerodynamic drag by adding airflow nozzles at the rear of its model and carrying out computational fluid dynamics simulations and analyses under the flow velocity of the jet port of 10, 20, and 30 m/s respectively, and meanwhile set up the airflow outlets at different locations of the model slope for simulation analyses under the flow velocity of the jet port of 20 m/s. The best up to 16.4% drag reduction rate is achieved in the simulations. The results show that the best drag reduction effect is achieved when the velocity of the jet outlet is 10 m/s. In contrast, the increase in the velocity of the jet outlet will lead to the early separation of the boundary layer, which in turn enhances its aerodynamic drag. As for different airflow outlets, while injecting airflow into the low-pressure region on the slope surface due to the boundary layer separation, moderately moving the jet port downward to enhance the pressure on the front and back of the model can achieve a better drag reduction effect.