Visualization by discharge illumination technique and modification by plasma actuator of rarefied Mach 2 airflow around a cylinder

Abstract

The use of plasma actuators for flow control has received considerable attention in recent years. This kind of device seems to be an appropriate means of raising abilities in flow control thanks to total electric control, no moving parts and a fast response time. The experimental work presented here shows, firstly, the non-intrusive character of the visualization of the density field of an airflow around a cylinder obtained using a plasma luminescence technique. Experiments are made in a continuous supersonic wind tunnel. The static pressure in the flow is 8 Pa, the mean free path is about 0.3 mm and the airflow velocity is 510 m s−1. Pressure measurements obtained by means of glass Pitot tube without the visualization discharge are proposed. Measured and simulated pressure profiles are in good agreement in the region near the cylinder. There is good correlation between numerical simulations of the supersonic flow field, analytical model predictions and experimental flow visualizations obtained by a plasma luminescence technique. Consequently, we show that the plasma luminescence technique is non-intrusive. Secondly, the effect of a dc discharge on a supersonic rarefied air flow around a cylinder is studied. An electrode is flush mounted on the cylinder. Stagnation pressure profiles are examined for different electrode positions on the cylinder. A shock wave modification depending on the electrode location is observed. The discharge placed at the upstream stagnation point induces an upstream shift of the bow shock, whereas a modification of the shock wave shape is observed when it is placed at 45° or 90°.

Computational and Experimental Modeling in Magnetoplasma Aerodynamics and High-Speed Gas and Plasma Flows (A Review)

“…Pulse-distributed surface «sliding» discharge (surface discharge with solid dielectric) of nanosecond duration (plasma sheet) can be used as a plasma actuator to affect flow [25][26][27][28][29]. It consists of surface-sliding dielectric channels (streamers, Figure 5), forming a plasma layer comparable in thickness to the boundary layer of supersonic flow (~0.5 mm).…”

Visualization of the interaction region of an oblique shock wave with a boundary layer by the radiation of a nanosecond surface sliding discharge

“…The usage of low-temperature plasma of surface discharges of various types (plasma actuators) in plasma aerodynamics is aimed to correct the flow regime, including the reduce of dynamic and thermal loads on the surface, controlling the laminar-turbulent transition in the boundary layer, the position of separation zones and shock waves [8][9][10], and the processes of combustion [11]. Pulsed distributed surface sliding discharge of nanosecond duration (plasma sheet) can be used as an actuator to influence the flow [9].…”

“…The short duration of nanosecond discharges (~ 100 ns) makes it possible to use the registration of radiation to visualize the structure of unsteady supersonic plane [12] and three-dimensional flows [13]. The radiation of glow-type discharges with a duration of more than one millisecond is mainly used to visualize the structure of stationary flows [10,14].…”