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Separation Control Using Plasma Actuators Experimental Studies Of Plasma Actuator Performance
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Book Synopsis Separation Control Using Plasma Actuators: Experimental Studies of Plasma Actuator Performance by : DartKen Poon
Download or read book Separation Control Using Plasma Actuators: Experimental Studies of Plasma Actuator Performance written by DartKen Poon and published by . This book was released on 2011 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Flow Control Techniques and Applications by : Jinjun Wang
Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2019 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master the theory, applications and control mechanisms of flow control techniques.
Book Synopsis Shock Wave-Boundary-Layer Interactions by : Holger Babinsky
Download or read book Shock Wave-Boundary-Layer Interactions written by Holger Babinsky and published by Cambridge University Press. This book was released on 2011-09-12 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.
Book Synopsis Recueil. Pièces diverses d'Albert Husson jouées de 1952 à 1974 by :
Download or read book Recueil. Pièces diverses d'Albert Husson jouées de 1952 à 1974 written by and published by . This book was released on 1952 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Investigation of Plasma Actuator Configurations for Flow Separation Control at Multiple Angles of Attack by : Thomas Kelsey West
Download or read book Numerical Investigation of Plasma Actuator Configurations for Flow Separation Control at Multiple Angles of Attack written by Thomas Kelsey West and published by . This book was released on 2012 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The primary objective of the study presented in this thesis was to analyze the effectiveness of aerodynamic plasma actuators as a means of active flow control over a low speed airfoil at multiple angles of attack each corresponding to two different flow separation mechanisms (i.e., laminar separation bubble and turbulent flow separation at stall conditions). Detailed parametric studies based on steady and unsteady Navier-Stokes simulations, modified to include the body force term created by the plasma actuator, were performed for a NACA 0012 airfoil at a chord Reynolds number of 105. In particular, parametric studies were performed to investigate the influence of the number, the location, the imposed body force magnitude (power input) and steady vs. unsteady operation of plasma actuators on the flow control effectiveness. First, the effectiveness of plasma actuators was studied when applied to the airfoil at a relatively low angle of attack, which involved the development of a laminar separation bubble (LSB). Next, the effectiveness of plasma actuators was analyzed at a high angle of attack where the stall of the airfoil occurs with a fully turbulent flow assumption. The results show that plasma actuators can provide significant improvement in aerodynamic performance for the flow conditions considered in this study. For LSB control, as much as a 50% improvement in the lift to drag ratio was observed. Results also show that the same improvement can be achieved using an unsteady or multiple actuators, which can require as much as 75% less power compared to a single, steady actuator. For the stalled airfoil case, as much as a 700% improvement in L/D was observed from a single, steady actuator. Note that this was achieved using a power input eight times higher than what was used for LSB control. Also, unsteady and multiple actuator configurations do not provide the same enhancement as the single, steady actuators. This was found to be due to the nature of the turbulent separation (trailing edge separation) at the stall condition that occurs for the selected airfoil and Reynolds number"--Abstract, leaf iii.
Book Synopsis Separation Control Using Plasma Actuators in a High Pressure Bend by : Michael J. Arthur
Download or read book Separation Control Using Plasma Actuators in a High Pressure Bend written by Michael J. Arthur and published by . This book was released on 2014 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advances in Effective Flow Separation Control for Aircraft Drag Reduction by : Ning Qin
Download or read book Advances in Effective Flow Separation Control for Aircraft Drag Reduction written by Ning Qin and published by Springer Nature. This book was released on 2019-10-17 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the results of a European-Chinese collaborative research project, Manipulation of Reynolds Stress for Separation Control and Drag Reduction (MARS), including an analysis and discussion of the effects of a number of active flow control devices on the discrete dynamic components of the turbulent shear layers and Reynolds stress. From an application point of view, it provides a positive and necessary step to control individual structures that are larger in scale and lower in frequency compared to the richness of the temporal and spatial scales in turbulent separated flows.
Book Synopsis Advanced UAV Aerodynamics, Flight Stability and Control by : Pascual Marqués
Download or read book Advanced UAV Aerodynamics, Flight Stability and Control written by Pascual Marqués and published by John Wiley & Sons. This book was released on 2017-07-11 with total page 799 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensively covers emerging aerospace technologies Advanced UAV aerodynamics, flight stability and control: Novel concepts, theory and applications presents emerging aerospace technologies in the rapidly growing field of unmanned aircraft engineering. Leading scientists, researchers and inventors describe the findings and innovations accomplished in current research programs and industry applications throughout the world. Topics included cover a wide range of new aerodynamics concepts and their applications for real world fixed-wing (airplanes), rotary wing (helicopter) and quad-rotor aircraft. The book begins with two introductory chapters that address fundamental principles of aerodynamics and flight stability and form a knowledge base for the student of Aerospace Engineering. The book then covers aerodynamics of fixed wing, rotary wing and hybrid unmanned aircraft, before introducing aspects of aircraft flight stability and control. Key features: Sound technical level and inclusion of high-quality experimental and numerical data. Direct application of the aerodynamic technologies and flight stability and control principles described in the book in the development of real-world novel unmanned aircraft concepts. Written by world-class academics, engineers, researchers and inventors from prestigious institutions and industry. The book provides up-to-date information in the field of Aerospace Engineering for university students and lecturers, aerodynamics researchers, aerospace engineers, aircraft designers and manufacturers.
Book Synopsis Optimisation of Dielectric Barrier Discharge Plasma Actuators and Their Application to Fluid Dynamics by : Rasool Erfani
Download or read book Optimisation of Dielectric Barrier Discharge Plasma Actuators and Their Application to Fluid Dynamics written by Rasool Erfani and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The standard dielectric barrier discharge (DBD) plasma actuator, in which an asymmetric arrangement of electrodes leads to momentum coupling into the surrounding air, has already demonstrated its capability for flow control. The effect of some parameters such as dielectric thickness, dielectric temperature, voltage amplitude, driving frequency, different configurations and arrangements on actuator performance are examined. The new configuration of DBD which uses multiple encapsulated electrodes (MEE) has been shown to produce a superior and more desirable performance over the standard actuator design. As the number of encapsulated electrodes increases and other variables such as the driving frequency and voltage amplitude are considered, finding the optimum actuator configuration for increasing the induced velocity becomes a challenge. The surrogate modelling optimisation provides a cheap and yet efficient method for systematically investigating the effect of different parameters on the performance of the plasma actuator. The effect of the optimum actuator configuration on the aerodynamic performance of an aerofoil under leading edge separation and wake interaction conditions is examined. The plasma actuator is placed at the leadingedge of a symmetric NACA 0015 aerofoil which corresponds to the location of the leading edge slat. The aerofoil is operated at a chord Reynolds number of 0.2×10 6. Surface pressure measurements along with the mean velocity profile of the wake using pitot measurements are used to determine the lift and drag coefficients, respectively. Particle image velocimetry (PIV) is also utilised to visualise and quantify the induced flow field. In comparison with reported literature on the standard DBD configuration, the MEE setup employed here is shown to provide a better means of flow control for the control of aerofoil separation. The characteristicsof a DBD plasma actuator when exposed to an unsteady flow generated by a shock tube is also investigated. This type of flow, which is often used in different studies, contains a range of flow regimes from sudden pressure and density changes to relatively uniform high-speed flow regions. A small circular shock tube is employed along with the schlieren photography technique to visualise the flow. The voltage and current traces of the plasma actuator are monitored throughout, and using the well established shock tube theory the change in the actuator characteristics are related to the physical processes which occur inside the shocktube. The results show that not only is the shear layer outside of the shock tube affected by the plasma but the passage of the shock front and high-speed flow behind it also greatly influences the properties of the plasma.
Book Synopsis Fundamental Physics and Application of Plasma Actuators for High-speed Flows by : Eli S. Lazar
Download or read book Fundamental Physics and Application of Plasma Actuators for High-speed Flows written by Eli S. Lazar and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, a detailed investigation is given discussing three plasma-based flow control methods. These methods included plasma generated by laser energy, microwaves, and electric arc. The plasma generated by laser energy was also applied to a sonic transverse jet in a supersonic cross flow. Lastly, the particle image velocimetry diagnostic was considered and a technique developed to evaluate measurement uncertainty and using experimental velocity data to solve for density from the continuity equation. In the laser-spark system, the effect of ambient pressure in the range of 0.1 to 1.0 atm and wavelength (266 nm and 532 nm) on the size, temperature, electron number density, and fraction of laser energy absorbed in a laser-induced plasma in air has been conducted. The plasma was generated by using optics to focus the laser energy. The focused laser pulse resulted in the induced optical breakdown of air, creating a plasma to perturb the flow field. As pressure or wavelength are reduced, the size of the plasma, its electron number density, and the fraction of incident laser energy that is absorbed are all found to decrease significantly. For the plasma generated by microwaves, the feasibility of using the system for flow control was demonstrated at pressures ranging from 0.05 atm to 1 atm and for pulsing frequencies between 400 Hz to 10 kHz. The setup was based on a quarter-wave coaxial resonator being operated with a microwave frequency of 2.45 GHz. Analysis of reflected power measurements suggested that the microwave energy could be best coupled into the resonator by using a small inductive loop, where the geometry can be experimentally optimized. The plasma was first characterized by recording images of the emission and taking temporal emission waveform profiles. Tests were conducted in quiescent air and analyzed with schlieren photography to determine the effectiveness of a plasma pulse to produce an instantaneous flow perturbation. Examination of phase averaged schlieren images revealed that a blast was produced by the emission and could be used to alter a flow field. The emission was also thermally characterized through emission spectroscopy measurements where the vibrational and rotational temperatures of the plasma were determined. The last system considered was a localized arc filament plasma actuator, or LAFPA-type device. The system creates electric arcs by generating electric fields in the range of 20 kV/cm between two pin-type electrodes. The potential of the actuator to influence surrounding quiescent flow was investigated using emission imaging, schlieren imaging, current and voltage probes, particle image velocimetry (PIV), and emission spectroscopy. The schlieren imaging revealed a potential to cause blast 0́−Mach0́+ waves and a synthetic jet with controllable directionality dependent on cavity orientation. The electric measurements revealed that, in order to increase the power discharged by the plasma, the electrode separation will only aid mildly and that an optimum plasma current exists (between 300-400 mA for the tested parameter space). The PIV data were acquired for various actuation frequencies and showed a trend between discharge frequency and maximum induced jet velocity. Finally, the emission spectroscopy data were acquired for four different cases: two electrode separations and two plasma currents. For each of the four conditions tested, the spectrum fit very well to a thermal distribution for early times in the emission. However, at later times in the emission, the spectrum no longer matched that of the second positive system under optically thick conditions for any combination of rotational and vibrational temperatures. Using the plasma generated by laser energy, an experimental investigation of flow control on a sonic underexpanded jet injected normally into a Mach 2.45 crossflow is reported. The jet exit geometry was circular and was operated at a jet-to-crossflow momentum flux ratio of 1.7. The unperturbed flow field was analyzed with schlieren imaging, PIV velocity data, surface oil flow visualizations, and pressure sensitive paint measurements. As a means of excitation to the flow field, the plasma energy was focused in the center of the jet exit at three different vertical locations. The perturbed resulting flow field was analyzed with schlieren photography and particle image velocimetry. Analysis of phase averaged schlieren images suggested that the resulting blast wave from the laser pulse disrupted the structure of the barrel shock and Mach disk. The two-component velocity field data revealed that the excitation pulse also caused a perturbation to the jet shear layer and induced the formation of vortices that convect downstream. Finally, additional techniques were developed for the PIV diagnostics. First, while PIV is an established experimental technique for determining a velocity field, quantifying the uncertainty related with this method remains a challenging task. To this end, four sources of uncertainty are assessed: equipment, particle lag, sampling size, and processing algorithm. An example uncertainty analysis is conducted for a transverse sonic jet injected into a supersonic crossflow. However, the analysis is not specific to the example flow field and may be generally applied to any mean velocity field. Secondly, using the velocity data from PIV, a technique was developed to solve for density from the continuity equation over the entire flow field. The technique is validated using data from CFD simulations and demonstrated for experimental data for two flow fields.
Book Synopsis Recent Progress in Some Aircraft Technologies by :
Download or read book Recent Progress in Some Aircraft Technologies written by and published by . This book was released on 19?? with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Computational Investigation of Plasma Actuator as an Active Flow Control Strategy of Laminar Separation Bubbles by : Justin Roger Aholt
Download or read book Computational Investigation of Plasma Actuator as an Active Flow Control Strategy of Laminar Separation Bubbles written by Justin Roger Aholt and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A parametric computational study designed to examine the plausibility of an external body force generated by active means, such as a plasma actuator, as a means of controlling a Laminar Separation Bubble (LSB) over an airfoil at low Reynolds numbers was conducted. Computational Fluid Dynamics (CFD) was employed to characterize the effect that a body force, localized to a small region tangent to the airfoil surface, might have on an LSB. In this study, the effects of altering the strength and location of the "actuator" on the size and location of the LSB and on the aerodynamic performance of the airfoil were observed. In a separate investigation, the effects of operating an actuator in a "burst" mode are investigated, where the effects of pulsing frequency and duty cycle are examined to determine whether further performance enhancements can be achieved via such means. It was found that the body force, when properly located and with sufficient magnitude, could effectively eliminate the LSB. Additionally, it was found that by eliminating the LSB, the aerodynamic efficiency of the airfoil could be improved by as much as 60%. Thus, it was determined that such a system may indeed be an effective measure of reducing or eliminating the negative effects associated with LSBs at low Reynolds numbers. Additionally, pulsed operation of the actuator was found to enhance effectiveness by as much as 20% over a power-equivalent steady actuator. These results indicate that such a control strategy may be an excellent candidate for future experimental research regarding this topic"--Abstract, leaf iii
Book Synopsis Plasma Actuators for Separation Control on Stationary and Oscillating Airfoils by : Martiqua L. Post
Download or read book Plasma Actuators for Separation Control on Stationary and Oscillating Airfoils written by Martiqua L. Post and published by . This book was released on 2004 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Robust Feedback Control of Flow Separation Using Plasma Actuators by : Laura Pasquale
Download or read book Robust Feedback Control of Flow Separation Using Plasma Actuators written by Laura Pasquale and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Active Flow Control by : Rudibert King
Download or read book Active Flow Control written by Rudibert King and published by Springer Science & Business Media. This book was released on 2007-08-29 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains contributions presented at the Active Flow Control 2006 conference, held September 2006, at the Technische Universität Berlin, Germany. It contains a well balanced combination of theoretical and experimental state-of-the-art results of Active Flow Control. Coverage combines new developments in actuator technology, sensing, robust and optimal open- and closed-loop control and model reduction for control.
Book Synopsis An Experimental Study of a Pulsed DC Plasma Flow Control Actuator by :
Download or read book An Experimental Study of a Pulsed DC Plasma Flow Control Actuator written by and published by . This book was released on 2006 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment on the effects of a pulsed DC plasma actuator on a separated flow in a low speed wind tunnel was conducted. The actuator consisted of two asymmetric copper electrodes oriented normal to the flow separated by a dielectric barrier and mounted on a flat plate in the center of the tunnel. A contoured insert was constructed and used to create an adverse pressure gradient in the test section comparable to a Pak-B low pressure turbine blade distribution. Suction was applied from the upper wall to induce separation along the flat plate over the electrodes. The DC power supply was kept constant at 8.5 kV and power was regulated through a high voltage fast transistor switch. The pulse width of the switch remained at 250 ns with the frequency ranging from 25 to 100 Hz. All studies were conducted at a Reynolds number of 30,000 to simulate takeoff and other low speed conditions. It was found that the DC pulsed plasma actuator could reattach the flow but not consistently at these conditions. Furthermore no evidence was found to indicate that coherent vortical structures are responsible for reenergizing the boundary layer and controlling separation.
Book Synopsis Experimental Investigation of Pulsed DBD Plasma Actuators for Aerodynamic Flow Control by : Philip Peschke
Download or read book Experimental Investigation of Pulsed DBD Plasma Actuators for Aerodynamic Flow Control written by Philip Peschke and published by . This book was released on 2014 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt:
