Mach 5 bow shock control by a nanosecond pulse surface dielectric barrier discharge

Abstract

Bow shock perturbations in a Mach 5 air flow, produced by low-temperature, nanosecond pulse, and surface dielectric barrier discharge (DBD), are detected by phase-locked schlieren imaging. A diffuse nanosecond pulse discharge is generated in a DBD plasma actuator on a surface of a cylinder model placed in air flow in a small scale blow-down supersonic wind tunnel. Discharge energy coupled to the actuator is 7.3–7.8 mJ/pulse. Plasma temperature inferred from nitrogen emission spectra is a few tens of degrees higher than flow stagnation temperature, T = 340 ± 30 K. Phase-locked Schlieren images are used to detect compression waves generated by individual nanosecond discharge pulses near the actuator surface. The compression wave propagates upstream toward the baseline bow shock standing in front of the cylinder model. Interaction of the compression wave and the bow shock causes its displacement in the upstream direction, increasing shock stand-off distance by up to 25%. The compression wave speed behind the bow shock and the perturbed bow shock velocity are inferred from the Schlieren images. The effect of compression waves generated by nanosecond discharge pulses on shock stand-off distance is demonstrated in a single-pulse regime (at pulse repetition rates of a few hundred Hz) and in a quasi-continuous mode (using a two-pulse sequence at a pulse repetition rate of 100 kHz). The results demonstrate feasibility of hypersonic flow control by low-temperature, repetitive nanosecond pulse discharges.

Dynamics of Rapid Localized Heating in Nanosecond Pulse Discharges for High Speed Flow Control

“…Also, compression waves generated in a NS-DBD actuator placed on the surface of a cylinder model in a Mach 5 flow were demonstrated to strongly perturb the bow shock in front of the model, which increased the shock stand-off distance, as shown in Fig. 3 [15].…”

Joule heating flow control methods for high-speed flows

“…Another interesting future study is based on the position control of impinging oblique shock waves through pressure waves generated by ns-DBD's, based on a similar outcome shown by Nishihara et al 30 examining bow shocks. Of course, these are just two examples of possible areas of future research that can be conducted.…”

“…This has benefits in improving the drag characteristics and reducing heat transfer. Nishihara et al 30 demonstrated that this was possible by applying a surface ns-DBD plasma actuator to a cylinder in a Mach 5 flow (a schematic of the ns-DBD used for this experiment is shown in figure 10). They achieved an increased stand-off distance of the bow shock by up to 25%.…”

“…A study carried out later by Bisek et al. 31 presented a comparison between experimental and numerical results for a configuration similar to Nishihara et al 30 Both 2D and 3D simulations were carried out using an aerothermodynamic Navier-Stokes code. A phenomenological model of dissipative heating was used for the ns-DBD, meaning that the numerical model of the actuator was based on empirical observations and assumptions.…”

Nitrogen Vibrational Population Measurements in the Plenum of a Hypersonic Wind Tunnel

“…The presence of vibrationally and electronically excited species in a hypersonic flow may strongly affect the emission signature from the shock layer. Finally, short-pulse electric discharges efficiently loading electronic energy levels of nitrogen and oxygen in air are currently being explored as means of hypersonic flow control by producing repetitive localized pressure perturbations in the flow [3].…”