Application of Active Flow Control on Generic 3D Car Models

The experimental investigations presented in this paper deal with an active flow control approach at the rear end of two different three-dimensional generic car configurations. Periodic forcing is used to influence the recirculation area behind these models based on the Ahmed body geometry with slant angles of 25 degrees and 90 degrees and hence to achieve a reduction in the total drag. Several forcing parameters (jet angle, forcing frequency and intensity) and their influence on the static pressure distribution at the rear end of the models and the total drag are examined. A model predictive closed-loop actuation approach is presented for one steady blowing excitation configuration. The interaction between the periodic compressed air actuator jet and the shear layer is depicted by means of stereo time-resolved Particle Image Velocimetry. The different actuation concepts lead to a drag reduction of up to 5.7% and demonstrate a good correlation with the static pressure distribution at the rear end of the model.