Analysis and Active Control of the Flow Around Two Following Ahmed Bodies

The aim of this work is on the one hand to show that the drag coefficient of a bluff body is mainly linked to the vortical structures in the close wake of the body. Thus an active control can be used to push away these structures to decrease the pressure forces at the back and consequently to reduce the drag coefficient. On the other hand a study of the platooning is performed. When two bodies are following each other with a short distance between them, the presence of the first body changes significantly the pressure force in front of the second one as a weak flow is present in between. The first body plays the role of a buckler and so the second body has to face completely different flow conditions. Therefore the drag of the second body is drastically reduced as shown on the results. Finally a control of the flow around the first body gives promising and surprising results.