Characterization of transverse plasma jet and its effects on ramp induced separation

Abstract

Plasma synthetic jet actuator (PSJA), which produces pulsed jets, is used to control the shock wave boundary layer interaction at a compression ramp at Ma=2.0. The flow topology of the wall jets from the PSJA is first visualised through particle laser scattering (PLS) photography. The PSJA aperture effect is also examined by comparing the jets out of the apertures of 1,2 mm and 2 mm respectively. The control effect is later investigated by both PLS and particle image velocimetry (PIV). , which was erupted from different jet apertures of 1.2mm and 2mm, were compared experimentally in a wind tunnel of Mach 2. Further, the interaction between the TPJ and the ramp induced separation was explored. The phase-locked two-component particle image velocimetry (PIV) and particle laser scattering (PLS) were used for flow visualizations. The K-H vortices and hairpin vortices due to the shear stress between the jet plume and high-speed mainstream were identified.The results show that the TPJ in supersonic flow is characterized by two typical parts: the attached jet plume (AJP) and the detached jet plume (DJP). The penetration height of the jet plume, which is closely related to the jet aperture, plays a dominant role in the proportion of the two parts. The higher jet penetration height leads to the more detached jet plume. As for the interaction between the jet plume and separation zone, the attached jet plume was blocked by the separation zone, which formed a recirculation zone and contributed to an expansion of the separation. In contrast, the detached jet plume transited along the shear layer and then enhanced the velocity exchange between the shear layer and mainstream. Ultimately, the reduction of the separation zone was revealed with the overall shear layer reduced. Furthermore, a conceptual model based on two typical morphological features was suggested to reveal the interaction mechanism.

Thermal effects on the performance of a nanosecond dielectric barrier discharge plasma actuator at low air pressure

“…An ionized wind will be generated near the wall when a pair of strip electrodes is set oppositely. 10 A spark discharge is applied in different actuators, such as plasma synthetic jet actuators (PSJAs) 11 and localized arc filament plasma actuators (LAFPAs). 12 A surface dielectric barrier discharge (DBD) plasma actuator, which is typically composed of four primary parts (a high-voltage power, an exposed electrode, an insulated electrode, and a dielectric barrier between these two electrodes) has been applied to a variety of flow control problems.…”

A computational study of leading-edge wall cooling effect on shock wave–boundary layer interaction in forward-facing step

“…All these investigations show the depth and strength of interaction flow, as well as create opportunities for a variety of passive and active control strategies. Many active and passive control approaches have been proposed to reduce the separation size induced by the shock wave/ boundary layer interaction, as well as the local heat flux rise, such as the micro-vortex generator, 16 a nearby wall alteration in the form of a bump, 17 the electromagnetic microjets, 18 the stable microjets, 19 the fluid jets, 20 and the synthesized jets. 21 The present study aims to figure out how incoming flow interacts with flow separations formed by an FFS.…”

Numerical Investigation of the Hypersonic Inlet under Throttling with Heat Source

“…Flow control is a key solution to the SWBLI challenge. Wang et al, [8] and Mengxiao et al, [9] used a transverse plasma jet to experiment and computationally regulate the SWBLI on a ramp in a supersonic flow. They observed that a high turbulence and temperature flow can worsen the separation barrier, and that the influence of plasma regulation on the boundary layer detachment is dependent on the Lorentz force vector.…”