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Chapitre D'ouvrage Année : 2020

Shear Layer and Shedding Modes Excitations of a Backward-Facing Step Flow by Surface Plasma Discharge

Résumé

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.
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Dates et versions

hal-02370358 , version 1 (19-11-2019)

Identifiants

Citer

Nicolas Benard, P. Sujar-Garrido, Jean-Paul Bonnet, E. Moreau. Shear Layer and Shedding Modes Excitations of a Backward-Facing Step Flow by Surface Plasma Discharge. Advances in Effective Flow Separation Control for Aircraft Drag Reduction, pp.55-74, 2020, 978-3-030-29687-2. ⟨10.1007/978-3-030-29688-9_3⟩. ⟨hal-02370358⟩
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