Control of Transitional and Turbulent Flows using Plasma Driven Fluidic Devices

Abstract

This numerical study explores the application of dielectric barrier discharge (DBD) plasma actuators inside a slot to generate steady suction for control of 2-D and 3-D transitional and turbulent flow over a flat plate. The numerical simulations employ a wellvalidated high-fidelity Navier-Stokes flow solver augmented with a phenomenological model that represents the plasma-induced time-average body force imparted by each actuator on the fluid. This study is broken into four parts: development of small disturbance waves over the baseline 2-D flat plate, examination of how adding a closed-end slot with no flow control affects the flat plate flow, employing four sets of plasma actuators inside an openended slot to control transition, and finally, extending the simulations to 3-D. Time and mesh resolution studies are performed for the flat plate without the slot. The addition of an inactive slot to the configuration tripped the boundary layer leading to the generation of multiple large vortical flow structures emanating from the slot opening. Activation of the DBD actuators with sufficient power eliminated small amplitude disturbances and significantly reduced turbulent kinetic energy which delayed transition to a location downstream of the computational domain. In 3-D, the flow over the baseline flat plate transitioned to turbulent flow which, when plasma based steady suction was employed, became laminar for the entire domain downstream of the slot.