Title: Pressure, temperature and free-flight projectile-displacement measurements during a plasma discharge generated on a supersonic projectile

Authors: Patrick Gnemmi; Christian Rey; Alfred Eichhorn; Myriam Bastide; Jean-Luc Striby

Addresses: French-German Research Institute of Saint-Louis (ISL), F-68301 Saint-Louis Cedex, France. ' French-German Research Institute of Saint-Louis (ISL), F-68301 Saint-Louis Cedex, France. ' French-German Research Institute of Saint-Louis (ISL), F-68301 Saint-Louis Cedex, France. ' French-German Research Institute of Saint-Louis (ISL), F-68301 Saint-Louis Cedex, France. ' French-German Research Institute of Saint-Louis (ISL), F-68301 Saint-Louis Cedex, France

Abstract: The generation of a plasma discharge on a projectile surface is a way of producing a pressure imbalance in order to divert a projectile from its initial trajectory. Thus, some experiments dealing with the steering of a supersonic projectile by using a plasma actuator are presented. The plasma discharge is produced by an embedded low-voltage generator capable of delivering a power controlled electric discharge between the electrodes flush with the projectile surface. A series of experiments carried out under wind-tunnel conditions at a Mach number of 3 allows surface-pressure and temperature measurements, which are synchronised with the visualisation of the perturbation evolution along the projectile surface, the disturbance being generated by the plasma discharge. Other series of experiments realised in a shock tunnel under 2.5 km of altitude real conditions at a Mach number of 4.5 demonstrates that a plasma discharge generates the angular deviation of an explosively-formed-projectile model: 120 J of stored energy delivered in 4.5 ms in front of the ogive-cylinder junction of the projectile induces an angle of attack of 11° after the plasma-discharge generation.

Keywords: supersonic flow; surface pressure measurement; temperature measurement; free-flight investigation; supersonic projectiles; projectile steering; Schlieren technique; differential interferometry; plasma discharge; projectile guidance; displacement measurement; visualisation; perturbation evolution; aerodynamics.

DOI: 10.1504/IJAD.2013.050915

International Journal of Aerodynamics, 2013 Vol.3 No.1/2/3, pp.84 - 104

Published online: 28 Feb 2014 *

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