Multidimensional Collisional Dielectric Barrier Discharge for Flow Separation Control at Atmospheric Pressures

Radio frequency based discharges at atmospheric pressures are the focus of increased interest in aerodynamics because of a wide range of potential applications including specifically actuation in flows at moderate speeds. Recent literature describing promising experimental observations, especially on separation control, have spurred efforts in the development of parallel theoretical modeling to alleviate limitations in current understanding of the actuation mechanism. The present effort builds on a recently developed finite element-based one- and two-dimensional multi-fluid formulation of plasma sheath for atmospheric optical glow discharge in partially ionized gas. The model was relatively straightforward but formed the foundation of a versatile first-principles based methodology. Higher-fidelity models are included to yield a more sophisticated framework to predict discharge-induced momentum exchange. Here, the complete problem of a dielectric barrier discharge based separation control with axially displaced electrodes is simulated in a self-consistent manner. Model predictions for transient evolution of charge densities, the electric field, electrodynamic force and induced gas velocity distributions for helium gas in quiescent condition are shown to mimic trends reported in the experimental literature. For the first time, results also document the decay process of a separation bubble formed due to flow past a flat plat inclined at 12 deg angle of attack. This effort sets the basis for extending the formulation further to include polyphase power input in multi-dimensional settings, and to apply the simulation method to flows past common aerodynamic configurations.
Presented at the AIAA Fluid Dynamics Conference (35th) and AIAA Plasma Dynamics and Lasers Conference (36th) held in Toronto, Canada on 6-9 June 2005. Supported in part by AFOSR.