The purpose of this paper is to describe experimental and numerical investigations focussed on the shock wave modification induced by a dc glow discharge. The model is a flat plate in a rarefied Mach 2 air flow, equipped with a plasma actuator composed of two electrodes. The natural flow without actuation exhibits a shock wave with a hyperbolic shape. When the discharge is on, the shock wave shape remains hyperbolic but the shock wave is pushed forward, leading to an increase in the shock wave angle. In order to discriminate thermal effects from purely plasma ones, the plasma actuator is then replaced by an heating element.
The experimental study is carried out with the super/hypersonic wind tunnel MARHy located at the ICARE Laboratory in Orléans. The experimental configuration with the heating element is simulated with a code using the 2D full compressible Navier-Stokes equations adapted for the rarefied conditions.
For heating element temperatures equal to the flat plate wall surface ones with the discharge on, experimental and numerical investigations showed that the shock wave angle was lower with the heating element, only 50 percent of the values got with the plasma actuator, meaning that purely plasma effects must also be considered to fully explain the flow modifications observed. The results obtained with the numerical simulations are then used to calculate the aerodynamic forces, i.e. the drag and the lift. These numerical results are then extrapolated to the plasma actuator case and it was found that the drag coefficient rises up to 13 percent when the plasma actuator is used, compared to only 5 percent with the heating element.
This paper matters in the topic of atmospheric entries where flow control, heat management and aerodynamic forces are of huge importance.
Romain Joussot’s fellowship is provided by the French Government’s Investissement d’Avenir program: Laboratoire d’Excellence CAPRYSSES (Grant No. ANR-11-LABX-0006-01). Additional funding is provided by the Région Centre with the PASS grant (Convention No. 00078782). The authors would furthermore like to acknowledge the constructive feedback from the reviewers.
Coumar, S., Joussot, R., Parisse, J.D. and Lago, V. (2016), "Influence of a plasma actuator on aerodynamic forces over a flat plate interacting with a rarefied Mach 2 flow", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 26 No. 7, pp. 2081-2100. https://doi.org/10.1108/HFF-07-2015-0285
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