Magnetoaerodynamic Actuator for Hypersonic Flow Control

The classic pressure interaction over a sharp leading edge is a unique feature of hypersonic flow in which the boundary layer interacts strongly with the oncoming stream. The present magnetoaerodynamic actuator is based on the fact that the plasma ignited on a surface can modify the boundary-layer displacement thickness. This electromagnetic perturbation to the flowfield is further amplified by the hypersonic viscous-inviscid interaction to produce a high-surface-pressure plateau on a microsecond scale. The induced surface pressure is an effective hypersonic flow control mechanism. In essence, the minuscule magnetoaerodynamic interaction adjacent to the solid surface is introduced as an added physical mechanism for flow control. The electromagnetic force enhanced inviscid-viscous interaction generates a greater high-pressure regime over the solid surface than that of the classic hypersonic pressure interaction. This plasma actuator is demonstrated by solving the two-dimensional magnetoaerodynamic equation including the Lorentz force and Joule heating. For plasma generated by secondary electronic emission, the well-known ionization formulation for thermal excitation is inapplicable. The drift-diffusion plasma model is adopted to describe the detailed electrodynamic structure of the glow discharge. The idea of a plasma actuator has been supported by preliminary experimental data at a Mach number of five.