| 1. |
- Benard, N., et al.
(author)
-
Shear Layer and Shedding Modes Excitations of a Backward-Facing Step Flow by Surface Plasma Discharge
- 2020
-
In: Advances in Effective Flow Separation Control for Aircraft Drag Reduction. - Cham : Springer. ; , s. 55-74
-
Book chapter (peer-reviewed)abstract
- The present experimental study interests in determining the influence of a linear plasma actuator (dielectric barrier discharge) on the development of a separated turbulent shear layer. More specifically, the plasma actuator is used to impose periodic perturbations at the step corner of a backward-facing step. Two different modes of excitation are explored. One concerns the shear layer mode of instability, a mode whose amplification leads to a minimization of the recirculation bubble. The present investigation shows how a dielectric barrier discharge plasma actuator can impose periodic perturbations that excite the shear layer mode and result in a strong regularization of the vortex street. The case of excitation at the shedding mode is also experimentally investigated using a DBD actuator. The measurements show the increase in Reynolds stress caused by this excitation as well as the specific growing mechanism of the shear layer. Indeed, phase-averaged flow measurements highlights the difference in the mechanism of development of the shear layer regarding the type of excitation used, the shear layer mode promoting a growing mechanism by fluid entrainment while the shedding mode enhancing the pairing of successive vortical flow structures.
|
|
