On the recirculating flow of three-dimensional asymmetric bluff bodies

The paper investigates the role of geometrical asymmetric modifications of a rectangular flat-backed body on the properties of the recirculating flow at a Reynolds number Re=1.8x10(5). The reference model has two reflectional symmetries denoted sy and sz in both spanwise directions. The flow is subjected to the static instability that leads to two mirrored wake states breaking the symmetry sy. Two families of geometrical variation of the fore-body and after-body are studied, each breaking one of the reflectional symmetries of the reference model. Geometrical modifications that preserve sy evidence possibilities of bistable dynamics suppression although the static instability persists. Geometrical modifications that do not preserve sy produces a large unbalance of both wake states in accordance to recent observations on real cars (Bonnavion et al. in J Wind Eng Ind Aerodyn 184:77-89, 2019). Results offer perspectives for potential drag reduction induced by appropriate coupling of bluff body geometry and wake state selection. [GRAPHICS]