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Computational Investigation Of Plasma Actuator As An Active Flow Control Strategy Of Laminar Separation Bubbles
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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 194 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 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 0 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 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 An Investigation of Dielectric Barrier Discharge Based Plasma Actuator Designs with Enhanced Performance In Active Flow Control by : Song Guo
Download or read book An Investigation of Dielectric Barrier Discharge Based Plasma Actuator Designs with Enhanced Performance In Active Flow Control written by Song Guo and published by . This book was released on 2013 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Parameter Studies of Various Plasma Actuator Concepts for Active Flow Control at Moderate Reynolds Numbers by : Pawel Piotrowski
Download or read book Experimental Parameter Studies of Various Plasma Actuator Concepts for Active Flow Control at Moderate Reynolds Numbers written by Pawel Piotrowski and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis AIAA Journal by : American Institute of Aeronautics and Astronautics
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2006 with total page 1380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Active Control of the Turbulent Flow Downstream of a Backward Facing Step with Dielectric Barrier Discharge Plasma Actuators by : Patricia Sujar Garrido
Download or read book Active Control of the Turbulent Flow Downstream of a Backward Facing Step with Dielectric Barrier Discharge Plasma Actuators written by Patricia Sujar Garrido and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is part of an international project (MARS) to improve air transport efficiency by active flow control strategy. In this context, the presented experimental works are focused on a surface Dielectric Barrier Discharge (DBD) as a solution to control the turbulent flow separation downstream a backward-facing step (BFS) at Reh = 30000. Two different plasma discharges are investigated: an ac-DBD resulting in a electrohydrodynamic force and a ns- DBD producing a pressure wave. Thanks to the versatility of plasma discharges and in order to optimize its effects on the flow, different locations of the DBD actuator have been investigated. Furthermore, an extended parametric study regarding the input variables of the discharge has been carried out by stereoscopic PIV. Among the obtained results, the mean reattachment length has been reduced up to 20%. In addition, other averaged quantities such as Reynolds stress components, the kinetic energy and the vorticity thickness of the separated shear layer have been analyzed to provide more extended information about the effects of the DBD actuator. The last part includes a dynamical analysis of the modifications produced by an optimal actuation. For that aim, the dominant structures are investigated by their signature in the frequency domain and by proper orthogonal decomposition (POD). All the results lead to the definition of an optimal actuation for which the mean reattachment position is reduced and the vortex shedding street can be reinforced by a lock-on control mechanism.
Book Synopsis Investigation of Magnetohydrodynamic Plasma Actuators for Aerodynamic Flow Control by : Brent Joel Pafford
Download or read book Investigation of Magnetohydrodynamic Plasma Actuators for Aerodynamic Flow Control written by Brent Joel Pafford and published by . This book was released on 2013 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the analysis, fabrication and testing of a novel magnetohydrodynamic plasma actuator for aerodynamic flow control, specifically, retreating blade stall. A magnetohydrodynamic plasma actuator is comprised of two parallel rail electrodes embedded chord-wise on the upper surface of an airfoil. A pulse forming network generates a low-voltage, high-current repetitive pulsed arc. Self-induced electromagnetic fields force the pulsed arc along the length of the rail electrodes at high velocities, transferring momentum to the surrounding air, creating a high-velocity pulsed air wall jet. A systematic experimental investigation of the effect of plasma actuators on the surrounding air is conducted in stagnant air conditions to gain an understanding of the physical characteristics. These characteristics include voltage and current measurements, pulsed arc velocity measurements, and high speed video imaging. The results show typical pulsed arc velocities of about 100 m/s can be induced with discharge energies of about 300 J per pulse. Additional experimental studies are conducted to quantify the performance of the pulsed arc for potential use in subsonic flow control applications. To gain an estimate of the momentum transferred from the pulsed arc to the surrounding air the plasma actuator is placed in a subsonic open-circuit wind tunnel at a Reynolds number of 4.5 x 105. The induced velocity of the pulsed wall jet is measured using a Laser Doppler Anemometer. The measurements show that the pulsed arc creates a high-velocity pulsed wall jet that extends 40 mm above the airfoils surface and has an induced velocity of 15 m/s greater than the unaltered air flow over the airfoil, with peak velocities of 32 m/s. The magnetohydrodynamic plasma actuator proved to induce velocities an order of magnitude greater than the velocities attained by current state-of-the-art plasma actuators. Moreover, the RailPAc is found to posses the potential for alleviation of retreating blade stall. Future work will include experiments to gain a detailed understanding of the improvements to the static stall angle, the optimal actuator geometry, excitation duty cycle, magnetic field augmentation, and behavior of the plasma armature at high Mach/Reynolds numbers. Particle Image Velocimetry (PIV) will be utilized to improve the induced flow velocity measurements acquired with the LDA.
Book Synopsis Scalability of Localized Arc Filament Plasma Actuators by : Clifford A. Brown
Download or read book Scalability of Localized Arc Filament Plasma Actuators written by Clifford A. Brown and published by BiblioGov. This book was released on 2013-07 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Temporal flow control of a jet has been widely studied in the past to enhance jet mixing or reduce jet noise. Most of this research, however, has been done using small diameter low Reynolds number jets that often have little resemblance to the much larger jets common in real world applications because the flow actuators available lacked either the power or bandwidth to sufficiently impact these larger higher energy jets. The Localized Arc Filament Plasma Actuators (LAFPA), developed at the Ohio State University (OSU), have demonstrated the ability to impact a small high speed jet in experiments conducted at OSU and the power to perturb a larger high Reynolds number jet in experiments conducted at the NASA Glenn Research Center. However, the response measured in the large-scale experiments was significantly reduced for the same number of actuators compared to the jet response found in the small-scale experiments. A computational study has been initiated to simulate the LAFPA system with additional actuators on a large-scale jet to determine the number of actuators required to achieve the same desired response for a given jet diameter. Central to this computational study is a model for the LAFPA that both accurately represents the physics of the actuator and can be implemented into a computational fluid dynamics solver. One possible model, based on pressure waves created by the rapid localized heating that occurs at the actuator, is investigated using simplified axisymmetric simulations. The results of these simulations will be used to determine the validity of the model before more realistic and time consuming three-dimensional simulations are conducted to ultimately determine the scalability of the LAFPA system.
Book Synopsis Wind Turbines by : Abdel Ghani Aissaoui
Download or read book Wind Turbines written by Abdel Ghani Aissaoui and published by BoD – Books on Demand. This book was released on 2016-07-27 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Renewable energies constitute excellent solutions to both the increase of energy consumption and environment problems. Among these energies, wind energy is very interesting. Wind energy is the subject of advanced research. In the development of wind turbine, the design of its different structures is very important. It will ensure: the robustness of the system, the energy efficiency, the optimal cost and the high reliability. The use of advanced control technology and new technology products allows bringing the wind energy conversion system in its optimal operating mode. Different strategies of control can be applied on generators, systems relating to blades, etc. in order to extract maximal power from the wind. The goal of this book is to present recent works on design, control and applications in wind energy conversion systems.
Book Synopsis Macroscopic Computational Model of Dielectric Barrier Discharge Plasma Actuators by : Timothy R. Klein
Download or read book Macroscopic Computational Model of Dielectric Barrier Discharge Plasma Actuators written by Timothy R. Klein and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Initial Study of Flow Control on a Single Stream Separated Shear Layer Using a Plasma Actuator by : Jennifer C. Nathman
Download or read book Initial Study of Flow Control on a Single Stream Separated Shear Layer Using a Plasma Actuator written by Jennifer C. Nathman and published by . This book was released on 2005 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Handbook of Wind Energy Aerodynamics by : Bernhard Stoevesandt
Download or read book Handbook of Wind Energy Aerodynamics written by Bernhard Stoevesandt and published by Springer Nature. This book was released on 2022-08-04 with total page 1495 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides both a comprehensive overview and deep insights on the state-of-the-art methods used in wind turbine aerodynamics, as well as their advantages and limits. The focus of this work is specifically on wind turbines, where the aerodynamics are different from that of other fields due to the turbulent wind fields they face and the resultant differences in structural requirements. It gives a complete picture of research in the field, taking into account the different approaches which are applied. This book would be useful to professionals, academics, researchers and students working in the field.
Book Synopsis Computational Study of Separation Control Using ZNMF Devices: Flow Physics and Scaling Laws by :
Download or read book Computational Study of Separation Control Using ZNMF Devices: Flow Physics and Scaling Laws written by and published by . This book was released on 2008 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of the proposed research was to gain a fundamental understanding of strategies, mechanisms, and scaling laws for successful control of separation using zern-net mass-flux (ZNMF) actuators. The key issue that was systematically studied was the optimal excitation frequencies in separated flows characterized by convective and/or global instabilities. The study was a complementary experimental/ numerical effort that capitalized on previous collaborations and was aimed at leveraging the respective strengths df CFD and experiments. The numerical component employed two different solvers will allowed us to investigate chord Reynolds numbers Re(c) up to O(10%). The complementary experiments use a large flat plate model equipped with a two-dimensional ZNMF actuator slot. Both the experiments and computations employed nonlinear spectral analysis to quantify quadratic coupling between the various instability mechanisms in separated flows. Outcomes included fundamental insights int0 the non-linear dynamics of separated airfoil flows and their implications for ZNMF separation control as well as development of improved lumped element design tool for ZNMF actuators in separation control applications.
Book Synopsis Low Reynolds Number by : Mustafa Serdar Genç
Download or read book Low Reynolds Number written by Mustafa Serdar Genç and published by BoD – Books on Demand. This book was released on 2012-04-04 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports the latest development and trends in the low Re number aerodynamics, transition from laminar to turbulence, unsteady low Reynolds number flows, experimental studies, numerical transition modelling, control of low Re number flows, and MAV wing aerodynamics. The contributors to each chapter are fluid mechanics and aerodynamics scientists and engineers with strong expertise in their respective fields. As a whole, the studies presented here reveal important new directions toward the realization of applications of MAV and wind turbine blades.
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:
Book Synopsis Case Study by : Nihar H. Chhatiawala
Download or read book Case Study written by Nihar H. Chhatiawala and published by . This book was released on 2018 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boundary Labs, LLC is an early-stage company composed of three students at Case Western Reserve University which aimed to evaluate the feasibility of commercialization of a novel dielectric barrier discharge (DBD) plasma actuator as an active flow control (AFC) method in wind turbines. The hypothesized benefits of DBD plasma actuators for AFC include improved energy capture from wind, low cost, and ease of implementation. This thesis is a two-part case study. The first part emulates a Small Business Innovation Research (SBIR) Phase I Proposal for the technology and includes discussions arguing that a strong commercial potential for the proposed technology exists in the United States and that technical development is feasible. The second part includes miscellaneous sections outside the scope of an SBIR proposal, leading to a discussion of the Boundary Labs team decision to discontinue development of this technology.
