Numerical Simulations Investigating Flow Over Flat Plate Suction Perforations Driven by Dielectric Barrier Discharge Plasma Actuation

Abstract

This numerical study explores the application of dielectric barrier discharge (DBD) plasma actuators inside a channel to generate steady suction for control of flow over a flat plate using 2-D slots and 3-D pipes. The numerical simulations employ a well-validated 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 two main parts. The first section focuses on 2-D flow and how the number of small slots (each 108 μm) and the streamwise spacing between them affects small disturbance growth. The second section explores the 3-D flow near a spanwise row of 1 mm perforations induced by plasma driven steady suction and how it is affected by plasma actuator power and the spanwise spacing of the holes. Results from the 2-D simulations demonstrate that multiple small slots driven by plasma actuation can significantly reduce the growth of disturbances. In fact with small levels of plasma actuation, the growth of disturbances injected at the leading edge of the flat plate can be eliminated for the entire length of the flat plate if more than seven slots were employed. For the flat plate with nine slots, the minimum value of plasma actuation power necessary to to generate steady suction was determined to be Dc = 4 at the given flow conditions. Four different spanwise spacings between three slots were also examined and found to have only a minor influence on the flow. For the 3-D flat plate with holes, the changes in the boundary layer are characterized as the actuator power is increased from 0 to Dc = 20. Described are detailed changes in the flow character and hole mass flow rates as Dc is increased. Additionally, the impact of spanwise spacing of the holes on the flat plate boundary layer is also explored. Unlike the 2-D flow which was virtually unaffected by streamwise slot spacing, the 3-D flow displayed significant feature changes as the spanwise hole spacing varied.