Effect of a transverse plasma jet on a shock wave induced by a ramp

Wang, Hongyu; Li, Jun; Jin, Di; Ding, Hui; Tian, Guohui; Wu, Yun

doi:10.1016/j.cja.2017.09.004

“…The control effect improves while the discharge energy and the orifice diameter increase, which is consistent with that in [83]. In [79,80], different configurations of the actuator array (i.e., spanwise, streamwise) were considered, and a longer modification of the shock wave system is demonstrated when actuators are arranged in the streamwise direction and triggered simultaneously. Yang et al [87] numerically investigated the control mechanism of SWBLI and concluded that the jet plume acts as a virtual micro vortex generator, which promotes the mixing within the turbulent boundary layer and enhances its ability to resist flow separation.…”

Section: Institutions Representative Literaturessupporting

confidence: 77%

“…Separation control at moderate-Reynolds number ONERA; Xiamen University; UNINA [35,72,73] Jet noise control ONERA [12,74,75] Shock wave/boundary layer interaction control UT Austin; AFEU; NUDT [18,[76][77][78][79][80][81][82][83] In separation control cases, PSJs are typically issued upstream of the separation region, either in the wall-normal direction to create a quasi-streamwise counter-rotating vortex pair [84] or pitched and skewed with respect to the main flow to produce a single dominant streamwise vortex [12]. These vortices transport the high-momentum flow from the outer boundary layer to the near-wall region, resulting in a fuller boundary layer velocity profile and a reduction in boundary layer shape factor (1.3-1.2 in [84]).…”

Section: Institutions Representative Literaturesmentioning

confidence: 99%

Plasma Synthetic Jet Actuators for Active Flow Control

Zong

¹

,

Chiatto

²

,

Kotsonis

³

et al. 2018

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The plasma synthetic jet actuator (PSJA), also named as sparkjet actuator, is a special type of zero-net mass flux actuator, driven thermodynamically by pulsed arc/spark discharge. Compared to widely investigated mechanical synthetic jet actuators driven by vibrating diaphragms or oscillating pistons, PSJAs exhibit the unique capability of producing high-velocity (>300 m/s) pulsed jets at high frequency (>5 kHz), thus tailored for high-Reynolds-number high-speed flow control in aerospace engineering. This paper reviews the development of PSJA in the last 15 years, covering the major achievements in the actuator working physics (i.e., characterization in quiescent air) as well as flow control applications (i.e., interaction with external crossflow). Based on the extensive non-dimensional laws obtained in characterization studies, it becomes feasible to design an actuator under several performance constraints, based on first-principles. The peak jet velocity produced by this type of actuator scales approximately with the cubic root of the non-dimensional energy deposition, and the scaling factor is determined by the electro-mechanical efficiency of the actuator (O(0.1%–1%)). To boost the electro-mechanical efficiency, the energy losses in the gas heating phase and thermodynamic cycle process should be minimized by careful design of the discharge circuitry as well as the actuator geometry. Moreover, the limit working frequency of the actuator is set by the Helmholtz natural resonance frequency of the actuator cavity, which can be tuned by the cavity volume, exit orifice area and exit nozzle length. In contrast to the fruitful characterization studies, the application studies of PSJAs have progressed relatively slower, not only due to the inherent difficulties of performing advanced numerical simulations/measurements in high-Reynolds-number high-speed flow, but also related to the complexity of designing a reliable discharge circuit that can feed multiple actuators at high repetition rate. Notwithstanding these limitations, results from existing investigations are already sufficient to demonstrate the authority of plasma synthetic jets in shock wave boundary layer interaction control, jet noise mitigation and airfoil trailing-edge flow separation.

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“…Therefore, in the current calculation, there are around 320,000 cells for each calculated case, and the comparison between the numerical simulation and the experiment was also made for a blunt body without a spike, as shown in Figure 3(b). In our simulation [30], the source term (defined as power density q h ) is determined by heating power P and volume of the heating zone V:…”

Section: Numerical Methodmentioning

confidence: 99%

Effects of Heat Addition on Wave Drag Reduction of a Spiked Blunt Body

Wang

¹

,

Yang

²

,

Li

³

et al. 2021

International Journal of Aerospace Engineering

Self Cite

2

0

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Drag reduction technology plays a significant role in extending the flight range for a high-speed vehicle. A wave drag reduction strategy via heat addition to a blunt body with a spike was proposed and numerically validated. The heat addition is simulated with continuous heating in a confined area upstream of the blunt body. The effects of heat addition on drag reduction in three flow conditions ( M = 3.98 , 5 , 6 ) were compared, and the influence of power density q h ( q 1 = 2.0 × 10 8 W / m 3 , q 2 = 5.0 × 10 8 W / m 3 , and q 3 = 1.0 × 10 9 W / m 3 ) of heating was evaluated. Results show that the heat addition has a positive way to reduce the drag of the body with a spike alone, and more satisfactory drag reduction effectiveness can be achieved at a higher Mach number. The drag reduction coefficient increases with q h in the same flow condition, with a maximum of 38.9% ( M = 6 ) as q 3 = 1.0 × 10 9 W / m 3 . The wave drag reduction principle was discussed by a transient calculation, which indicates that the separation region has entrainment of the heated air and expanded with its sonic line away from the blunt cone, which results in an alleviation of the pressure load caused by shock/shock interaction.

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“…The voltage and current evolutions in this case are shown in Fig.4. The characteristics of arc discharge have been reported by Wang [41] in detail. In the present experiment, the discharge duration td is about 20µs, which is limited by the capacitance.…”

Section: Uncertainty Analysismentioning

confidence: 99%

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

Tang

¹

,

Wang

²

,

Wang

³

et al. 2018

Experimental Thermal and Fluid Science

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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.

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Effect of a transverse plasma jet on a shock wave induced by a ramp

Cited by 37 publications

References 48 publications

Plasma Synthetic Jet Actuators for Active Flow Control

Plasma Synthetic Jet Actuators for Active Flow Control

Effects of Heat Addition on Wave Drag Reduction of a Spiked Blunt Body

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

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