Forcing three-dimensional large-scale flow asymmetries in the wake of blunt body : wake equilibrium and drag reduction

Y. Haffner (1) , J. Borée (1) , Andreas Spohn (1) , T. Castelain (2) , M. Michard (2) , Sylvie Sesmat (3) , Eric Bideaux (3)

1 PPrime [Poitiers] - Institut Pprime [UPR 3346]
2 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique
3 MIS - Ampère, Département Méthodes pour l'Ingénierie des Systèmes

We experimentally study the effect of high-frequency fluidic forcing on various asymmetric turbulent wakes behind a blunt body at ReH = 5 .105 . Different wake asymmetries are obtained by the use of passive perturbations around the body modifying the wake equilibrium. High-frequency forcing of the wake along the rear edges is then applied to increase the base pressure. Depending on the initial unforced wake vertical equilibrium, localized forcing along the top or bottom edges may strongly increase or decrease the base pressure. The efficiency of spatially localized forcing and the fluidic boat-tailing thus created is linked to the global wake equilibrium and its modification

Mots clés: turbulent wakes; drag reduction; Flow control

Domaines: Sciences de l'ingénieur [physics]

Y. Haffner, J. Borée, Andreas Spohn, T. Castelain, M. Michard, et al.. Forcing three-dimensional large-scale flow asymmetries in the wake of blunt body : wake equilibrium and drag reduction. Third international conference in numerical and experimental aerodynamics of road vehicles and trains (Aerovehicles 3), Jun 2018, Milan, Italy. ⟨hal-02405608⟩