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Author: National Aeronautics and Space Adm Nasa Publisher: Independently Published ISBN: 9781724014078 Category : Science Languages : en Pages : 30
Book Description
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
Author: National Aeronautics and Space Adm Nasa Publisher: Independently Published ISBN: 9781724014078 Category : Science Languages : en Pages : 30
Book Description
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
Author: Ning Qin Publisher: Springer Nature ISBN: 3030296881 Category : Technology & Engineering Languages : en Pages : 341
Book Description
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.
Author: Jordi Jurado Chillida Publisher: ISBN: Category : Languages : en Pages :
Book Description
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.
Author: Rudibert King Publisher: Springer Science & Business Media ISBN: 364211735X Category : Technology & Engineering Languages : en Pages : 417
Book Description
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.
Author: Julie Anne Lovato Publisher: ISBN: Category : Aerofoils Languages : en Pages : 130
Book Description
"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.
Author: National Aeronautics and Space Adm Nasa
Author: National Aeronautics and Space Adm Nasa
Author: S. S. Ravindran
Author: S. S. Ravindran
Author: Ning Qin
Author: Jinjun Wang
Author: Matthew Boucher
Author: Mark Feero
Author: Jordi Jurado Chillida
Author: Rudibert King
Author: Julie Anne Lovato