Plasmas in high speed aerodynamics

Abstract

A review is presented of the studies in the former Soviet Union and in the USA of the mutual interactions of plasmas and high speed flows and shocks. There are reports from as early as the 1980s of large changes in the standoff distance ahead of a blunt body in ballistic tunnels, significantly reduced drag and modifications of travelling shocks in bounded weakly ionized gases. Energy addition to the flow results in an increase in the local sound speed that leads to expected modifications of the flow and changes to the pressure distribution around a vehicle due to the decrease in local Mach number. The critical question was, did a plasma provide a significant energy multiplier for the system? There have been a large number of experimental studies on the influence of a weakly ionized plasma on relatively low Mach number shocks and inherently also on the influence of the shock on the plasma. This literature is reviewed and illustrated with representative examples. The convergence through more controlled experiments and improved modelling to a physics understanding of the effects being essentially due to heating is outlined. It is demonstrated that the heating in many cases is global; however, tailored experiments with positive columns, dielectric barrier discharges and focused microwave plasmas can produce very localized heating. The latter appears more attractive for energy efficiency in flow control. Tailored localized ionization and thermal effects are also of interest for high speed inlet shock control and for producing reliable ignition for short residence time combustors, and work in these areas is also reviewed.

Influence of shock wave propagation on dielectric barrier discharge plasma actuator performance

“…[11][12][13][14] Specifically, in high-speed flows, several experimental studies have demonstrated the influence of the plasma on shock wave. [15][16][17][18] Many of these investigations have been performed with shock waves, generated by an electrically pulsed discharge, propagating along the low-pressure-unconstricted dc glow discharge.…”

Flow control in a supersonic inlet model by electrical discharge

“…Comparing with mechanical one, the method of high-speed §ow control based on plasma deposition possesses, at least, two advantages: inertialess and §exibility (electronic control of magnitude and location of plasma impact). Numerous potential applications can be considered (still extemporized in the most cases) for this technique [3,7].…”

Nonequilibrium Plasma Aerodynamics

“…Currently, the problem of flow active control by low-temperature plasma is considered to be one of the most booming realms of aerodynamics [Bletzinger et al, 2005, Moreau, 2007. One of the main practical advantages of plasma-assisted flow control is its zero reaction time.…”

“…That is why the plasma mechanisms of external flow modification, shock wave reconfiguration and drag force reduction were considered as an important alternative to traditional solutions for thermal management [Bletzinger et al, 2005]. The paper [Klimov et al, 1982] was one of the first articles devoted to the impact of plasma effects on shock wave propagation.…”

“…These schemes included novel approaches for plasma generation, magnetohydrodynamic (MHD) flow control and power generation and new hot gas counter-flows and other purely thermal approaches [Bletzinger et al, 2005]. The first of these highly innovative concepts of the aircraft called AJAX (Ayaks) was developed by Vladimir Freishtadt in the late 1980s.…”