Download or read book Active Control of Flow Separation Over an Airfoil written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-25 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing an aircraft without conventional control surfaces is of interest to aerospace community. In this direction, smart actuator devices such as synthetic jets have been proposed to provide aircraft maneuverability instead of control surfaces. In this article, a numerical study is performed to investigate the effects of unsteady suction and blowing on airfoils. The unsteady suction and blowing is introduced at the leading edge of the airfoil in the form of tangential jet. Numerical solutions are obtained using Reynolds-Averaged viscous compressible Navier-Stokes equations. Unsteady suction and blowing is investigated as a means of separation control to obtain lift on airfoils. The effect of blowing coefficients on lift and drag is investigated. The numerical simulations are compared with experiments from the Tel-Aviv University (TAU). These results indicate that unsteady suction and blowing can be used as a means of separation control to generate lift on airfoils. Ravindran, S. S. Langley Research Center NASA/TM-1999-209838, NAS 1.15:209838, L-17932

Download or read book Active Control of Flow Separation Over an Airfoil written by S. S. Ravindran and published by . This book was released on 1999 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Active Control of Flow Separation Over an Airfoil written by S. S. Ravindran and published by . This book was released on 1999 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Active Control of Flow Separation and Structural Vibrations of a S809 Airfoil written by Matthew Boucher and published by . This book was released on 2009 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Control of Separation on a Low Reynolds Number Airfoil Using Synthetic Jet Actuation written by Mark Feero and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluidic Active Flow Control of Boundary Layer Separation on Supercritical Airfoil written by Jordi Jurado Chillida and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Presently, during critical phases of flight like takeoff, landing or approach, aircrafts need systems as flaps or slats that helps them to improve lift. Those, hydraulic or mechanical, are deployed during these phases in order to increase the wing surface and consequently, lift. Focusing on the wing, an airfoil is a cross-sectional shape of it; therefore, we can find many configurations or designs with different properties. Specifically, many airplanes use NACA series but, a few years ago, commercial aircraft like Airbus A380 or Boeing 787, or military aircrafts like Boeing C-17 Globemaster are using Supercritical NASA (SC) that improve the global efficiency. In particular, this final degree project is focused on the analysis of the flow on the boundary layer in supercritical airfoil when the airplane is flying at low Reynold numbers. This analysis has been done at different angle of attack in order to analyze the behavior and limits of this airfoil. With this study, basis is established to design a fluidic active flow control with the purpose of reducing aircraft mechanical systems and its problems related with weight, maintenance and failures. For example, when we will be landing at BCN, instead of listen and see a complex system deploying on the wing, we will see a jet on the wing that makes the same effects. Many simplifications have been done possible because we are working at low Reynolds. One of the most important is to work with incompressible flow. Also, an approximation of the supercritical airfoil selected to process and study the behavior is done. About simulations, software like gmsh, Nektar++ or Paraview has been used for the processing to obtain numerical results. Finally, after analyzing simulations results, the optimal angle to deploy the systems is defined. And for this, the fluidic active flow control is going to be implemented to recover the lift.

Download or read book Active Flow Control II written by Rudibert King and published by Springer Science & Business Media. This book was released on 2010-04-06 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interest in the field of active flow control (AFC) is steadily increasing. In - cent years the number of conferences and special sessions devoted to AFC org- ized by various institutions around the world continuously rises. New advanced courses for AFC are offered by the American Institute of Aeronautics and Ast- nautics (AIAA), the European Research Community on Flow, Turbulence and Combustion (ERCOFTAC), the International Centre for Mechanical Sciences (CISM), the von Karman Institute for Fluid Dynamics (VKI), to name just a few. New books on AFC are published by prominent colleagues of our field and even a new periodical, the ‘International Journal of Flow Control’, appeared. Despite these many activities in AFC it was felt that a follow-up of the highly successful ‘ACTIVE FLOW CONTROL’ Conference held in Berlin in 2006 was appropriate. As in 2006, ‘ACTIVE FLOW CONTROL II’ consisted only of invited lectures. To sti- late multidisciplinary discussions between experimental, theoretical and numerical fluid dynamics, aerodynamics, turbomachinary, mathematics, control engineering, metrology and computer science parallel sessions were excluded. Unfortunately, not all of the presented papers made it into this volume. As the preparation and printing of a book takes time and as this volume should be available at the conf- ence, the Local Organizing Committee had to set up a very ambitious time sch- ule which could not be met by all contributors.

Download or read book Active control of the separation region on a two dimensional airfoil written by Julie Anne Lovato and published by . This book was released on 1992 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This experimental analysis presents a comprehensive study of the separating boundary layer over a static airfoil under natural and actively controlled conditions. Near-surface hot-film and surface pressure measurements, as well as flow visualization are used to analyze the large-scale nature of the flow over a two-dimensional NACA-0015 airfoil and determine forcing effects. Results from the static study are then extended for an initial evaluation of unsteady airfoil control. Results show that the fundamental frequency associated with free shear layer instabilities for this case is an integral multiple of the frequency associated with wake structures. The static separating boundary layer response to active control confirms that it is a boundary layer transitioning to a free shear layer. Qualitative analyses show that significant reduction in overall static separation can be achieved under forcing conditions. Upper airfoil surface suction values are also significantly increased over the natural values. Applying tangential pulsed air control at static fundamental frequencies to a dynamic airfoil results in delay of the dynamic stall vortex formation and a delay of dynamic stall. These discoveries indicate that the developed control methodology may prove successful in increasing unsteady aircraft maneuverability. Subject terms: Static Airfoil Control; Separation Control; Unsteady Aerodynamics; Boundary Layer Control."--Report documentation page.

Download or read book Active Flow Separation Control of a Laminar Airfoil at Low Reynolds Number written by Nathan Owen Packard and published by . This book was released on 2012 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Detailed investigation of the NACA 643-618 is obtained at a Reynolds number of 6.4x104 and angle of attack sweep of -5°

Download or read book Proceedings of SAI Intelligent Systems Conference IntelliSys 2016 written by Yaxin Bi and published by Springer. This book was released on 2017-08-22 with total page 1084 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings of the SAI Intelligent Systems Conference 2016 (IntelliSys 2016) offer a remarkable collection of papers on a wide range of topics in intelligent systems, and their applications to the real world. Authors hailing from 56 countries on 5 continents submitted 404 papers to the conference, attesting to the global importance of the conference’s themes. After being reviewed, 222 papers were accepted for presentation, and 168 were ultimately selected for these proceedings. Each has been reviewed on the basis of its originality, novelty and rigorousness. The papers not only present state-of-the-art methods and valuable experience from researchers in the related research areas; they also outline the field’s future development.

Download or read book Numerical Investigation of Active Flow Control Applied to an Airfoil Leading Edge written by Bhanu Prakash Reddy Samala and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Objectives: The major objective of the Master Thesis proposal is to perform 2D computational study and compare the enhancement in the global aerodynamic coefficients, mainly lift and drag coefficients, for cases of with and without Active Flow Control (AFC). The focus is also on various cases of parameters of active flow control i.e, frequency of fluid ejection, jet velocity from actuator and location of slots for actuators for delaying the airfoil leading edge separation. Introduction: In the present context, the focused area is an airfoil of a regular commercial plane. The major concern while conducting experimental or numerical fluid dynamics study with the airfoils is to delay the separation of air (fluid) on both of the pressure sides on wing. The two main locations where the separation of fluid have an impact on global lift and drag coefficients include the leading edge boundary layer and the separation on the trailing edge flap.(Ciobaca & Wild, 2013). The techniques to delay the separation layer are of two major types which include Active Flow Control(AFC) and Passive Flow Control (PFC) (Jansen, 2012). The reason to choose AFC for this case is the reliability of the technique for all the future developments in various sectors like aerospace, automobile, wind energy etc (Nasa Website news 2013 [5][6]). Active Flow Control is becoming a viable tool for modifying flows for many practical applications. Active flow control can enable the design of simpler, smaller and more aerodynamically efficient structures that help reduce aircraft weight, drag, and fuel consumption. It typically refers to the use of time-dependent (often periodic) disturbances that are introduced into the flow field by the actuators. Also, AFC modifies the flow by adding energy (blowing) or by removing energy (suction). Methodology: As aforementioned, the proposed thesis focus is on computational study of the airfoil leading edge boundary layer with and without AFC. The variation of global lift and drag coefficients on varying the parameters of Active Flow Control like frequency, jet velocity and location of slots. The research conducted by (Burt Gunther et.al 2010) on AFC for airfoil flap will be used as guidance for conducting the similar test cases for Leading Edge AFC. The preliminary results from the computational model will be compared with the existing experimental results obtained at TU Braunschweig and DLR, Germany (Ciobaca & Wild, 2013) to check the accuracy and reliability of the numerical simulation results in order to further contribute to the existing state of the art results. To develop the computational model, the NACA2412 is chosen. The initial focus is on incompressible flow conditions by choosing the appropriate turbulence model and other numerical methods for solving Unsteady Reynolds Averaged Navier Stokes (URANS) Equations. Depending upon the accuracy of the results when compared with the experimental results, there will always be a flexibility to improvise the results using more computationally intensive numerical methods. The major software tools that will be used include a combination of ANSYS Fluent and OpenFOAM. References: 1. Ciobaca, V., & Wild, J. (2013). An Overview of Recent DLR Contributions on Active Flow-Separation Control Studies for High- Lift Configurations, (6), 1-12. 2. Generators, V., & Jansen, D. P. (2012). Passive Flow Separation Control on an Airfoil-Flap Model, (August). 3. Nagib, P. H. M., Kiedaisch, J. W., Wygnanski, P. I. J., Stalker, A. D., Wood, T., & Mcveigh, M. A. (n.d.). First-In- Flight Full-Scale Application of Active Flow Control : The XV-15 Tiltrotor Download Reduction.

Download or read book Active Flow Control written by Rudibert King and published by Springer Science & Business Media. This book was released on 2007-05-31 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.

Download or read book Control of Flow Separation written by Paul K. Chang and published by Hemisphere Pub. This book was released on 1976 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Aerodynamics of Heavy Vehicles Trucks Buses and Trains written by Rose McCallen and published by Springer Science & Business Media. This book was released on 2004-09 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes the carefully edited contributions to the United Engineering Foundation Conference: The Aerodynamics of Heavy Vehicles: Trucks, Buses and Trains held in Monterey, California from December 2-6, 2002. This conference brought together 90 leading engineering researchers discussing the aerodynamic drag of heavy vehicles. The book topics include a comparison of computational fluid dynamics calculations using both steady and unsteady Reynolds-averaged Navier-Stokes, large-eddy simulation, and hybrid turbulence models and experimental data obtained from wind tunnel experiments. Advanced experimental techniques including three-dimensional particle image velocimetry are presented as well, along with their use in evaluating drag reduction devices.

Download or read book Separation of Flow written by Paul K. Chang and published by Elsevier. This book was released on 2014-06-28 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interdisciplinary and Advanced Topics in Science and Engineering, Volume 3: Separation of Flow presents the problem of the separation of fluid flow. This book provides information covering the fields of basic physical processes, analyses, and experiments concerning flow separation. Organized into 12 chapters, this volume begins with an overview of the flow separation on the body surface as discusses in various classical examples. This text then examines the analytical and experimental results of the laminar boundary layer of steady, two-dimensional flows in the subsonic speed range. Other chapters consider the study of flow separation on the two-dimensional body, flow separation on three-dimensional body shape and particularly on bodies of revolution. This book discusses as well the analytical solutions of the unsteady flow separation. The final chapter deals with the purpose of separation flow control to raise efficiency or to enhance the performance of vehicles and fluid machineries involving various engineering applications. This book is a valuable resource for engineers.