Plasma Actuator for Hypersonic Flow Control

Abstract

A summary of recent research progress in hypersonic plasma actuators for flow control is attempted. The most effective plasma actuator is derived from an electromagnetic perturbation to the growth rate of a shear layer and amplified by the strong viscous-inviscid interaction. Computational efforts that use a driftdiffusion and a simple phenomenological plasma model, as well as, experiments in a hypersonic plasma channel have shown the effectiveness of using electroaerodynamic interaction as a hypersonic flow control mechanism. In principle, the plasma actuator based on magneto-aerodynamic interaction should have an added mechanism in the Lorentz force to be even more effective as a flow control mechanism. However, this approach also incurs additional challenges due to the Hall effect for experimental and computational simulations. Magneto-aerodynamic interactions have also been demonstrated for separated flow control, albeit in a very limited scope. Numerical simulations based on a simple phenomenological plasma model have shown the feasibility for separated flow suppression in shockboundary-layer interaction over a compression ramp at a hypersonic flow of Mach 14.1. The control mechanism relies on the Lorentz force to energize the retarded shear layer in the viscous interacting region, but the effectiveness of momentum transfer via inelastic collision requires further validation. Nomenclature