The use of plasma actuators has been seen as an effective means for controlling flow over plates, airfoils, and turbine blades. Plasma actuators have been demonstrated, experimentally and numerically, as a potentially effective method for boundary layer control (Corke et al. 2006). Unlike many active methods of boundary layer control, plasma actuators are attractive because they can be easily implemented on a number of different geometries. This boundary layer control is driven by a body force vector tangent to the surface in which the actuator is integrated.

A linear single dielectric barrier discharge plasma actuator consists of two offset rectangular electrodes separated by a dielectric. The two electrodes can be subjected to an AC voltage source either one hundred and eighty out of phase or one of the electrodes can serve as a ground and the other is subjected to AC voltage. The parameter space needed to be explored for plasma
actuators is large since the performance is sensitive to geometry and material properties. Plasma actuators essentially inject momentum tangent to the surface in which they are mounted. This has been modeled as a body force vector in the vicinity above the embedded electrode. The presentation will describe the development of a mathematical model for this phenomenon for use in the unstructured CFD code UNCLE and the structured CFD code GHOST.

Numerical simulations of plasma actuators have been done with the structured grid based code GHOST, developed by Y.B. Suzen and P.G. Huang at the University of Kentucky, and have been verified by experimental results from Jacob et al. 2006. These computations were done by calculating the body force vector as the product of the electric potential in the computational domain with that of the net charge density in the working fluid. Appropriate Neumann and Dirichlet boundary conditions were also considered at the boundaries of different parts of the domain (i.e. electrodes, solid dielectric, and fluid). The body force was then inserted as a source term in the momentum computations. This model抯 development is based on Maxwell抯 equations and the characteristic length of plasma (the Debye length). The exposed electrode is a source for the potential due to the electric field and the embedded electrode is a source for the net charge density.

Thus far, results from UNCLE include the calculation of the normalized electric field potential distribution through two-dimensional domains. The presentation presents the mathematical model used to describe the effects of the plasma actuator in more detail. The results present the effects of plasma actuators on quiescent flow in a two-dimensional domain in the vicinity of the electrodes. A comparison of two-dimensional results from UNCLE with the results from GHOST is also discussed. The presentation also includes quantitative comparisons of experimental results presented by Jacob et al. 2006.