Gasdynamic Flow Control by Ultrafast Local Heating in a Strongly Nonequilibrium Pulsed Plasma

Abstract— The paper presents a review of modern works on gasdynamic flow control using a highly nonequilibrium pulsed plasma. The main attention is paid to the effects based on ultrafast (on the nanosecond time scale for atmospheric pressure) local gas heating, since, at present, the main successes in controlling high-speed flows by means of gas discharges are associated with this thermal mechanism. Attention is paid to the physical mechanisms responsible for the interaction of the discharge with gas flows. The first part of the review outlines the most popular approaches for pulsed energy deposition in plasma aerodynamics: nanosecond surface barrier discharges, pulsed spark discharges, and femto- and nanosecond optical discharges. The mechanisms of ultrafast heating of air at high electric fields realized in these discharges, as well as during the decay of the discharge plasma, are analyzed separately. The second part of the review gives numerous examples of plasma-assisted control of gasdynamic flows. It considers control of the configuration of shock waves in front of a supersonic object, control of its trajectory, control of quasi-stationary separated flows and layers, control of a laminar–turbulent transition, and control of static and dynamic separation of the boundary layer at high angles of attack, as well as issues of the operation of plasma actuators in different weather conditions and the use of plasma for the de-icing of a flying object.

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Effect of a High Electric Field on the Thermal and Phase Change Characteristics of an Impacting Drop

ASME 2019 Heat Transfer Summer Conference ◽

10.1115/ht2019-3649 ◽

2019 ◽

Author(s):

Abhishek Basavanna ◽

Prajakta Khapekar ◽

Navdeep Singh Dhillon

Keyword(s):

Heat Transfer ◽

Electric Field ◽

Phase Change ◽

Electric Fields ◽

High Speed ◽

Impact Behavior ◽

Liquid Drops ◽

Active Interest ◽

Post Impact ◽

High Electric Fields

Abstract The effect of applied electric fields on the behavior of liquids and their interaction with solid surfaces has been a topic of active interest for many decades. This has important implications in phase change heat transfer processes such as evaporation, boiling, and condensation. Although the effect of low to moderate voltages has been studied, there is a need to explore the interaction of high electric fields with liquid drops and bubbles, and their effect on heat transfer and phase change. In this study, we employ a high speed optical camera to study the dynamics of a liquid drop impacting a hot substrate under the application of high electric fields. Experimental results indicate a significant change in the pre- and post-impact behavior of the drop. Prior to impact, the applied electric field elongates the drop in the direction of the electric field. Post-impact, the recoil phase of the drop is significantly affected by charging effects. Further, a significant amount of micro-droplet ejection is observed with an increase in the applied voltage.

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Driftgeschwindigkeit und Beweglichkeit von Elektronen in Silicium bei 4,2 °K in Abhängigkeit vom elektrischen Feld / Driftvelocity and Mobility of Electrons in Silicon at 4.2 °K in Dependence of Electric Field

Zeitschrift für Naturforschung A ◽

10.1515/zna-1972-0105 ◽

1972 ◽

Vol 27 (1) ◽

pp. 26-30

Author(s):

P. Deimel

Keyword(s):

Electric Field ◽

Electric Fields ◽

Silicon Surface ◽

Surface Barrier ◽

Surface Barrier Detector ◽

Direct Information ◽

Fully Depleted ◽

Barrier Detector ◽

High Electric Fields ◽

Silicon Surface Barrier Detector

Abstract The pulse rise times of an n-type silicon surface barrier detector were measured at 4.2 °K. At this temperature the detector was fully depleted even at very low bias and the measured pulse rise times gave direct information about the driftvelocity and the mobility. Instead of E-0.5, an E-0.8 dependence of the mobility at moderate electric fields was found. At high electric fields agreement exists with theory.

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Numerical investigation of hypersonic flow with repetitive-pulsed plasma actuators

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410017703417 ◽

2017 ◽

Vol 232 (9) ◽

pp. 1715-1724

Author(s):

Chin-Cheng Wang ◽

Li-Chung Hsu

Keyword(s):

Circular Cylinder ◽

Flow Control ◽

Hypersonic Flow ◽

High Speed ◽

Numerical Study ◽

Pressure Ratio ◽

Plasma Actuators ◽

Circular Cylinders ◽

Pulsed Plasma ◽

Pulsed Discharges

Repetitive-pulsed plasma actuators have become the key enabler for flights in the hypersonic flow control. A numerical study focuses on the effect of the repetitive-pulsed plasma actuators at Mach 6. The geometric effects of circular, square, and triangular cylinders as well as a sphere on the aerodynamic performance are considered in the present study. For flow over the circular cylinder and sphere, shock control by repetitive-pulsed discharges is investigated, respectively. The baseline results are successfully validated with the theoretical and published numerical values for flow past a circular cylinder at Mach 6. Without flow control, results show that the shapes of the triangular cylinder and sphere have much smaller high-pressure regions compared to that of the square and circular cylinders. With repetitive-pulsed plasma, the time-average drag reduction has been reduced by a maximum of 0.8% and the stagnation pressure ratio is reduced by 2.1% for Mach 6 flow over a circular cylinder. Thus, this research shows a great benefit of repetitive-pulsed discharges to the state-of-the-art in high-speed flight design.

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Atomic Spectroscopy in the FIM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145157 ◽

1986 ◽

Vol 44 ◽

pp. 758-761

Author(s):

J. J. Hren ◽

S. D. Walck

Keyword(s):

Electron Microscope ◽

Electric Fields ◽

Atom Probe ◽

Atomic Spectroscopy ◽

Single Atom ◽

Statistical Sampling ◽

Commercial Instrument ◽

Available Technology ◽

High Electric Fields ◽

Field Ion Microscope

The field ion microscope (FIM) has had the ability to routinely image the surface atoms of metals since Mueller perfected it in 1956. Since 1967, the TOF Atom Probe has had single atom sensitivity in conjunction with the FIM. “Why then hasn't the FIM enjoyed the success of the electron microscope?” The answer is closely related to the evolution of FIM/Atom Probe techniques and the available technology. This paper will review this evolution from Mueller's early discoveries, to the development of a viable commercial instrument. It will touch upon some important contributions of individuals and groups, but will not attempt to be all inclusive. Variations in instrumentation that define the class of problems for which the FIM/AP is uniquely suited and those for which it is not will be described. The influence of high electric fields inherent to the technique on the specimens studied will also be discussed. The specimen geometry as it relates to preparation, statistical sampling and compatibility with the TEM will be examined.

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