The actuations generated by the plasma synthetic jet actuator (PSJA) may become weak under multiple pulses when discharge frequency increases. In order to further study characteristics of actuations, high-speed Schlieren method is adopted for experimental on a nanosecond (NS-PSJA) made machinable ceramic. Three typical working states are captured numbers measurements, which continuous, critical, and discontinuous states. For deep understanding, relationship between NS-PSJA discussed in two...

Sliding dielectric barrier discharge (SL-DBD) has demonstrated significant potential for flow control to enhance the aerodynamic performance of aircraft. The paper investigates velocity characteristics SL-DBD-induced structures during non-starting phase in continuous mode using particle image velocimetry. results reveal that induced exhibits periodic fluctuations phase, and dominance rotation strain rates determines structure characteristics. When rate dominates, vortex behavior. Moreover,...

In this study, we propose a scheme to control the deflection of warhead based on configuration hypersonic glide body (HGB) solve problems posed by its large surface load and severe aerodynamic heat under flight conditions. We conducted numerical simulations configurations an HGB analog different modes as well varying angles directions deflection. The results showed that once had been deflected, overall still exhibited static longitudinal stability. An increase in angle significantly reduced...

Pulsed surface arc discharge (PSAD) is one of the essential techniques in flow control. In this paper, effects electrode configuration on heat transfer characteristics PSAD and disturbance field were investigated by thermal imaging technology high-speed photography technology. By defining curvature curve (COC) electrode, we physical mechanism configuration, affecting disturbed field. The results show that COC has optimal solution COCopt. When ≤ COCopt, smaller COC, more concentrated...

The plasma synthetic jet actuator (PSJA) has been proven to have potential for shock wave control in the supersonic/hypersonic flow. To evaluate possibility PSJA applied hypersonic inlet under a Mach number greater than design value and provide deeper understanding of its mechanism, relevant two-dimensional numerical simulations are carried out. Based on discussions about results, effects clear actuations generated by PSJAs, including diffracted waves, jets, discharged heat, oblique waves...

To delay the position of vortex breakdown and increase lift characteristics flying wing aircraft, a aircraft under jet flow control were studied based on numerical simulation. The design idea excitation selection natural helical mode frequency is proposed. fields spectrum before after applying steady unsteady are analyzed. results show that same momentum coefficient, method has more advantages. effect in range instability generally better than outside mode. When consistent with peak value...

A better understanding of the mechanism flow separation suppression by a dielectric barrier discharge is essential for control. This paper investigates improving aerodynamic performance airfoil when Reynolds number in range 6 × 104–4 105. The results show that disturbance gas to field will form new structure. fluctuating frequency structure determines ability plasma actuator suppress separation. investigation improves and develops

Nitrate is an important source of nitrogen and also acts as a signaling molecule to trigger numerous physiological, growth, developmental processes throughout the life plant. Many nitrate transporters, transcription factors, protein kinases participate in regulation signaling. Here, we identified gene encoding chrysanthemum calcineurin B-like interacting kinase CmCIPK23, which participates pathways. In Arabidopsis, overexpression CmCIPK23 significantly decreased lateral root number length...

An experimental study was conducted with the aim of alleviating vertical tail buffeting a 55° delta wing using pulsed nanosecond dielectric barrier discharge plasma actuators. The flow physics in event stall, reattachment, vortex breakdown, shear layer under actuation were obtained and analyzed, results indicate that promotes attachment manipulates layer. acceleration structural response increases an increasing angle attack, first bending mode most significantly at post-stall angle....

In this work, the Direct Numerical Simulation (DNS) and Oil-Film Interferometry (OFI) technique are used to investigate hypersonic boundary layer transition induced by single double roughness elements at Mach number 5. For roughness, DNS results showed that both horseshoe vortices hairpin caused shear instability can affect instability. The generation of near-wall unstable structure is key point behind element. At downstream element, interaction between will spread in spanwise direction....

Detailed phase-lock schlieren measurement was conducted to study the physical evolution process of structures inside plasma synthetic jet actuator driven by a high voltage nanosecond pulse. One strong blast wave and heat source core are generated immediately after arcing discharge. Within cavity, as is reflected cavity walls interacts with core, pressure gas increased rapidly series diffractive comes out from orifice followed train vortex rings speed jet.

An experimental investigation of the actuation characteristics a repetitive nanosecond pulsed dielectric barrier discharge from bending plasma actuators mounted on sharp edge is conducted. Four with different angles are tested and compared planar actuator in quiescent air using schlieren imaging electrical measurements. The results show that when fed by same pulse, morphology, current waveform, energy consumption very similar. However, thermal perturbations induced flows differ...

The present study investigates the discharge and flow characteristics of a sliding (SD) driven by alternating current (AC) negative direct (DC) high voltage in continuous operation burst-mode actuation quiescent air. burst frequency f is set at 20, 40, 50, 100 Hz with duty cycle τ fixed 50%. Different cases exhibit similar morphologies electrical properties. results indicate that induced horizontal body force generated SD undergoes following stages: formation, intensification, accumulation,...

The transient flow structures produced by a pulsed nanosecond plasma actuator and the mechanism which they are generated investigated experimentally through simulations for case of control on non-slender delta wing. Phase-averaged particle image velocimetry reveals phenomenon in which, after each discharge pulse, two sub-vortices sequence move along shear layer regardless angle attack, this is confirmed hot-wire anemometry. However, at high actuation frequencies (F+ = fc/U∞ ≥ 6.435), double...

Jet flow-control technology is a promising area of fluid research. In this work, the effect curved-surface jet in an incoming flow Mach = 5 and its underlying control mechanism are experimentally studied using high-speed photography dynamic force measurement. From establishment complete stability field, evolutionary process can be roughly divided into five stages: two equilibrium stages (short long term), acceleration stage, bow shock formation interference removal stable state. By defining...

The complete flow structure and the composition of generated by Pulsed Surface Arc Discharge in a Magnetic Field (M-PSAD) are keys to explaining plasma application mechanism. experimental results show that M-PSAD can produce clusters detonation waves. thermal motion charged particles cluster is main reason for effect arc discharge. wave consists shock wave, Taylor expansion two different thickness zones particles. provide profound physical mechanism applying plasma.

The sliding dielectric barrier discharge (SL-DBD) has attracted attention due to its ability suppress flow separation. This paper investigated the effect of SL-DBD on field in flat plate boundary layer by time-resolved particle image velocimetry. We obtained finite-time Lyapunov exponent and Lagrangian coherent structures through velocity field. results show spatial differences, will produce a “strong–weak–strong” directionality structure induced is main reason for difference. induce large...

With the rapid development of Chinese economy, flight delay becomes more and serious brings a lot complaints emergency situations, present situation in our country various influencing factors is analyzed. Related statistic characteristics are given by mathematical analysis computation. Some measures to reduce put forward from an integrated systematic viewpoint, which related air traffic control departments, airlines airports.