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Accueil du site > Thèmes de recherche > Propulsion spatiale & écoulements à grande vitesse > 3.2 Écoulements hypersoniques > 3.2.2 Contrôle d’écoulements supersoniques

3.2.2 Contrôle d’écoulements supersoniques

Two approaches are developed at ICARE for supersonic flow control : the uses of plasma actuators and the application of standard mechanical methods.

3.2.2.1 Flow control with plasmas
This activity was initiated in 2004 concerning the effects of a surface electrical discharge over a flat plate. The discharge is created by two electrodes glued on the surface of the plate. Experiments were performed in the MARHy wind tunnel operating with air at Mach 2 under low density conditions. Heating of the cathode has been observed by an infrared camera. This heating, due to ionic bombarding and recombination at the surface is higher as the electrical potential increases. Pitot probe measurements demonstrated a thickening of the boundary layer when the upstream electrode is the cathode. The effect is weak or even inexistent when the downstream electrode is active. It is thus inferred that the discharge effect is directly connected to the heating of the plate. When the upstream part of the plate is hot, the boundary layer is more influenced by the heating. This study was supported by the Region Centre and the EPEE federation ; it also benefited from collaboration with the Laboratorio de Fluidodinámica, Universidad de Buenos Aires (TH15 ; ACL146, ACL155, ACL158, ACL162, ACTI84, ACTI87, ACTI89, ACTI90, ACTI104, ACTI105, ACTI110, ACTI118, ACTI119, ACTI120, ACTN4, ACTN5, ACTN6).

3.2.2.2 Thrust vectorization of an axisymmetric nozzle
An experimental and numerical investigation is ongoing to examine the possibilities of fluid-based thrust vectorization in an axisymmetric nozzle through the injection of a secondary gas into a supersonic primary stream. Experiments are performed in the super/hypersonic wind-tunnel EDITH with a Mach 3 nozzle. By way of a Schlieren flow vizualisation technique it was so far shown that side gas flow injection induces a shock inside the nozzle, the latter being at the origin of a change in the main stream direction. This activity is the subject of a PhD thesis in the framework of a cooperation with the LEEM (Université d’Evry) ; it is supported by the CNES (ACTI127).

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