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Characterization And Control Of Vortex Breakdown Over A Delta Wing At High Angles Of Attack
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Book Synopsis Characterization and Control of Vortex Breakdown Over a Delta Wing at High Angles of Attack by : Anthony M. Mitchell
Download or read book Characterization and Control of Vortex Breakdown Over a Delta Wing at High Angles of Attack written by Anthony M. Mitchell and published by . This book was released on 2000-08-01 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demands for more maneuverable and stealthy air vehicles have encouraged the development of new control concepts for separated flows. The goalof this research is the control of leading-edge vortex breakdown by open-loop, along-the-core blowing near the apex of a delta wing to improve lift and maneuverability at high angles of attack. Control is dependent on the knowledge of and the ability to detect principle characteristics of the phenomena. Therefore, an experimental study of a 700 delta wing was accomplished to better understand the physical properties of the vortical flow and the vortex breakdownphenomena. Multiple experimental methods were used to characterize the flow field and its influence on the model's surfaces as well as to identify parameters for closed-loop feedback control.
Book Synopsis Computational Fluid Dynamics Investigation of Vortex Breakdown for a Delta Wing at High Angle of Attack by : Jacob A. Freeman
Download or read book Computational Fluid Dynamics Investigation of Vortex Breakdown for a Delta Wing at High Angle of Attack written by Jacob A. Freeman and published by . This book was released on 2003-03-01 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the commercially available FLUENT 3-D flow field solver, this research effort investigated vortex breakdown over a delta wing at high angle of attack (a) in preparation for investigation of active control of vortex breakdown using steady, along- core blowing A flat delta-shaped half-wing with sharp leading edge and sweep angle of 600 was modeled at a 180 in a wind tunnel at Mach 0,04 and Reynolds number of 3,4 x 10(sub 5). A hybrid (combination of structured and unstructured) numerical mesh was generated to accommodate blowing ports on the wing surface. Results for cases without and with along-core blowing included comparison of various turbulence models for predicting both flow field physics and quantitative flow characteristics, FLUENT turbulence models included Spalart-Allmaras (S-A), Renormalization Group k-e, Reynolds Stress (RSM), and Large Eddy Simulation (LES), as well as comparison with laminar and inviscid models. Mesh independence was also investigated, and solutions were compared with experimentally determined results and theoretical prediction, These research results show that, excepting the LES model for which the computational mesh was insufficiently refined and which was not extensively investigated, none of the turbulence models above, as implemented with the given numerical grid, generated a solution which was suitably comparable to the experimental data. Much more work is required to find a suitable combination of numerical grid and turbulence model.
Book Synopsis Velocity Field Over Delta Wings at High Angles of Attack by : Devin O. O'Dowd
Download or read book Velocity Field Over Delta Wings at High Angles of Attack written by Devin O. O'Dowd and published by . This book was released on 1999-02-01 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of vortex breakdown over delta wings at high angles of attack (AOA) has been an interest to researchers, mathematicians, and aircraft designers for decades. It is a very hot topic as it relates to many aircraft being designed today and because no complete understanding exists. Most of the understanding that does exist comes in the form of the problems associated with vortex breakdown. Many question if it is possible to control the breakdown to avoid the problems and to aid the aircraft in maneuverability. The purpose of this study is to lay the foundation for future research at the University of Washington, so that the identity to the cause of the vortex breakdown may be found.
Book Synopsis Structure and Control of Three-Dimensional Unsteady Flow in Delta Wings at High Angle-of-Attack by :
Download or read book Structure and Control of Three-Dimensional Unsteady Flow in Delta Wings at High Angle-of-Attack written by and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This program has focused on the instantaneous flow structure generated by controlled motion of wings in the pitching and rolling modes, as well as application of local control techniques for mediating the flow structure. The instantaneous flow structure is characterized using high-image-density particle image velocimetry, in conjunction with new types of two and three dimensional imaging techniques. This approach provides instantaneous velocity fields, streamline patterns and vorticity distributions at crucial locations in the flow field and allows a proper basis for eventual control of the flow structure. Characterization of the flow structure in the rolling mode of wing motion has involved definition of the critical states of the flow, based on the static locations of onset of vortex breakdown. The instantaneous crossflow and streamwise topology has been defined as a function of row angle. For pitching motion of the wing, simultaneous maneuver of the wing and application of control in the form of deflection of a leading-edge flap and blowing from the trailing-edge provide an effective, interactive means of altering the onset of vortex breakdown, thereby enhancing the effectiveness of maneuvers at high angle of attack.
Author :North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Special Course Publisher : ISBN 13 : Total Pages :154 pages Book Rating :4.3/5 (243 download)
Book Synopsis Special Course on Aircraft Dynamics at High Angles of Attack: Experiments and Modelling by : North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Special Course
Download or read book Special Course on Aircraft Dynamics at High Angles of Attack: Experiments and Modelling written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Special Course and published by . This book was released on 1991 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This report consists of lecture notes of an AGARD Fluid Dynamics Panel Special Course. These notes provide the latest information on the development and use of dynamic experiments in wind tunnels from several of the NATO nations. They address current oscillatory and rotary test techniques, experimental results for typical configurations, and the use of these data for flight mechanics applications. Subject included are: dynamic lift, wing rock, fluid dynamics of rotary flows, mathematical modelling, non-linear data representation, vortex manipulation for control enhancement, and correlations of predictions based on rotary and oscillatory wind-tunnel and flight-test results. The complete course notes are contained in two volumes. The main part of the notes is contained in AGARD Advisory Report 265 (ADA235179). The present volume includes papers on: Unsteady aerodynamics of slender wings; Dynamic stall effects and applications to high performance aircraft; Oscillatory test techniques; Large amplitude oscillations; Oscillatory data for typical configurations; and Forebody vortex control."--Stinet.
Book Synopsis High Angle of Attack Aerodynamics by : Josef Rom
Download or read book High Angle of Attack Aerodynamics written by Josef Rom and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerodynamics of aircraft at high angles of attack is a subject which is being pursued diligently, because the modern agile fighter aircraft and many of the current generation of missiles must perform well at very high incidence, near and beyond stall. However, a comprehensive presentation of the methods and results applicable to the studies of the complex aerodynamics at high angle of attack has not been covered in monographs or textbooks. This book is not the usual textbook in that it goes beyond just presenting the basic theoretical and experimental know-how, since it contains reference material to practical calculation methods and technical and experimental results which can be useful to the practicing aerospace engineers and scientists. It can certainly be used as a text and reference book for graduate courses on subjects related to high angles of attack aerodynamics and for topics related to three-dimensional separation in viscous flow courses. In addition, the book is addressed to the aerodynamicist interested in a comprehensive reference to methods of analysis and computations of high angle of attack flow phenomena and is written for the aerospace scientist and engineer who is familiar with the basic concepts of viscous and inviscid flows and with computational methods used in fluid dynamics.
Book Synopsis Interaction, Bursting and Dynamic Control of Vortices of a Cropped Double-delta Wing at High Angle of Attack by : Abdullah M. Alkhozam
Download or read book Interaction, Bursting and Dynamic Control of Vortices of a Cropped Double-delta Wing at High Angle of Attack written by Abdullah M. Alkhozam and published by . This book was released on 1994 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flow visualization study of the vortical flow over a cropped double-delta wing model with sharp leading edges and its three derivatives with small geometric modifications (fillets) at the strake wing junction was conducted in the Naval Postgraduate School water tunnel using the dye-injection technique. The fillets increased the wing area of the baseline model by 1%. The main focus of this study was to evaluate the effect of fillets on vortex core trajectories, interactions and breakdown on the leeward surface at high angle of attack (AOA) with zero sideslip angle. Comparison of test results for different fillet shapes indicates delay in both vortex interaction and breakdown at high AOA, particularly for the diamond fillet shapes. The vortex breakdown data implies lift augmentation for both static and dynamic case, with the static data correlating well with recently published numerical data. High angle-of-attack aerodynamics, Effect of fillets on vortex core trajectories, Interaction and breakdown, Flow visualization by dye-injection technique, Static and dynamic water tunnel studies on double-delta wings.
Book Synopsis Article de presse sur "Le Chevalier d'Harmental", musique d'André Messager by :
Download or read book Article de presse sur "Le Chevalier d'Harmental", musique d'André Messager written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Interaction, Bursting and Control of Vortices of A Cropped Double-Delta Wing at High Angle of Attac by :
Download or read book Interaction, Bursting and Control of Vortices of A Cropped Double-Delta Wing at High Angle of Attac written by and published by . This book was released on 1994 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flow visualization study of the vortical flow over a cropped double-delta wing model with sharp leading edges and its three derivatives with small geometric modifications (fillets) at the strake wing junction was conducted in the Naval Postgraduate School water tunnel using the dye-injection technique. The fillets increased the wing area of the baseline model by 1%. The main focus of this study was to evaluate the effect of fillets on vortex core trajectories, interactions and breakdown on the leeward surface at high angle of attack (AOA) with zero sideslip angle. Comparison of test results for different fillet shapes indicates delay in both vortex interaction and breakdown at high AOA, particularly for the diamond fillet shapes. The vortex breakdown data implies lift augmentation for both static and dynamic case, with the static data correlating well with recently published numerical data. High angle-of-attack aerodynamics, Effect of fillets on vortex core trajectories, Interaction and breakdown, Flow visualization by dye-injection technique, Static and dynamic water tunnel studies on double-delta wings.
Book Synopsis An Experimental Investigation of the Passive Control of Reverse Delta Wing Vortex Flow Structure and Aerodynamics Characteristics by : Hongzhi Mou
Download or read book An Experimental Investigation of the Passive Control of Reverse Delta Wing Vortex Flow Structure and Aerodynamics Characteristics written by Hongzhi Mou and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis summarises an experimental study of a 65-sweep reverse delta wing (RDW) by using a seven-hole pressure probe and a two-component force balance at Re = 270,000. Dye water flow visualization was also conducted in order to better understand the flow structure. Particular emphasis was placed on the variation of vortex flow quantities and critical flow parameters such as the core circulation, total circulation, tangential velocity and axial core velocity with change in chordwise locations from x/c = 0.2 to x/c = 1.5 for [alpha] = 10°- 22°. Based on lift measurements, the RDW generated less lift from [alpha] = 8° to [alpha] = 35° in comparison with the conventional delta wing (DW). Hence, lift augmentation was attempted by attaching passive control devices such as a side edge strip (SES) and a leading edge strip (LES), made from aluminum strips with different widths, which were placed perpendicularly to the wing's bottom surface. The flow field scans showed that the vortex flow underwent diffusion while it progressed in the chordwise direction. The size of the separated flow region, which originated from the spanwise vortex breakdown, increased with the angle of attack. Compared to a baseline RDW, RDW with SES generated a pair of more concentrated vortices with a higher core and total circulation values. Compared to a baseline RDW, the lift coefficient generated by the RDW with a 1.5% c SES and a 3% c SES increased by 0.18 to 0.28 on average, for angles of attack ranging from 0° to 40°. In addition, 1.5% c and 3% c SES boosted the wing's lift-to-drag ratio, for an average of 24% and 5%, respectively, from angles of attack of 10° to 20°. The dye flow visualization showed that the vortex flow generated by the RDW was located outside of the wing's surface and the vortex generated by the DW is located above the wing surface, in which suggesting the vortex lift is not applicable to a RDW. " --
Book Synopsis An Analysis of the Delta-wing Hypersonic Stability and Control Behavior at Angles of Attack Between 30° and 90° by : David E. Fetterman
Download or read book An Analysis of the Delta-wing Hypersonic Stability and Control Behavior at Angles of Attack Between 30° and 90° written by David E. Fetterman and published by . This book was released on 1963 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unsteady Three-dimensional Aerodynamic Flow by : Donald Rockwell
Download or read book Unsteady Three-dimensional Aerodynamic Flow written by Donald Rockwell and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this program is to determine the instantaneous flow structure on delta wings at high angle of attack as well as from cylindrical bodies, which are subjected to basic classes of motion. New techniques of high image density particle image velocimetry provide the instantaneous vorticity fields and streamline patterns, thereby allowing interpretation of the underlying physics using critical point theory. This type of quantitative interpretation of the flow structure is crucial for performing vorticity balances on wings and bodies and thereby optimization of overall performance characteristics. Furthermore, for the case of the delta wing at high angle of attack, local control techniques are applied simultaneously at leading and trailing edges of the wing, in order to alter the crucial features of vortex breakdown and subsequent large scale stall. Such control techniques have application to a wide variety of separated flows from wings and cylindrical bodies.
Book Synopsis An Experimental Investigation of Aerodynamics and Flow Characteristics of Slender and Nonslender Delta Wings by : Muneeb Dogar
Download or read book An Experimental Investigation of Aerodynamics and Flow Characteristics of Slender and Nonslender Delta Wings written by Muneeb Dogar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The leading-edge vortical flow structure over a 65 slender (DW65) and a 50 non-slender (DW50) delta wing was investigated at Reynolds number of order 105. Particular emphasis was placed in the variation of vortex flow quantities and critical flow parameters with change in angle of attack and chordwise distance. In addition, the progression of vortex breakdown with angle of attack was documented based on pressure and three-dimensional velocity information. A glimpse of wake-vortex evolution was also discussed. Moreover, aerodynamic lift and drag forces were evaluated based on wake survey analyses and compared with direct force balance measurements. Special attention was focused on drag characterization based on lift dependency where Maskell formulation was adopted for the estimation of induced drag. The results showed that the flow over DW65 and DW50 has some qualitative resemblances but quantitatively they are two contrasting flows. Prior to the breakdown, in the case of DW65, the vortical flow is near-axisymmetric but in the case of DW50, the vortex and axial core never matches and even the definition of distinctive vortex center is often ambiguous except at higher angles of attack, moreover the axial core was always accompanied by large momentum deficit. The variation of vortex flow quantities in streamwise direction showed self-similar behavior when plotted against radial distance scaled by local semi-span while interestingly for DW50 self-similar behavior was showed only by the variation of total pressure loss about the pressure core. It was established that the flow over DW50 was marred by an active interaction of vortical and boundary layer flow due to the close proximity of vortex to the wing surface. For the first time the progression of vortex breakdown over the wing surface was reported on the basis of three-dimensional flow information which elucidated the respective indicators of breakdown for slender and non-slender delta wings. Lastly, wake survey analyses were carried and comparison of different lift computational models and direct measurement were presented. Moreover, the estimation of profile drag is sensitive to the definition of wake region whereas vortex breakdown upstream of trailing-edge resulted in underestimation and overestimation of induced drag and CL, respectively. For all the cases of slender wing and high angle of attack cases of non-slender delta wing showed that the induced drag always constituted more than 50% of the total drag. The results provided here provided a deepened and extended insight on vortical and aerodynamics characteristics of slender and non-slender delta wing. " --
Book Synopsis Multiple-actuator Control of Vortex Breakdown on a Maneuvering Delta Wing and Related Issues of Low Analysis and Topology by : Peter V. Vorobieff
Download or read book Multiple-actuator Control of Vortex Breakdown on a Maneuvering Delta Wing and Related Issues of Low Analysis and Topology written by Peter V. Vorobieff and published by . This book was released on 1996 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unsteady Three-Dimensional Aerodynamic Flow by :
Download or read book Unsteady Three-Dimensional Aerodynamic Flow written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this program is to determine the instantaneous flow structure on delta wings at high angle of attack as well as from cylindrical bodies, which are subjected to basic classes of motion. New techniques of high image density particle image velocimetry provide the instantaneous vorticity fields and streamline patterns, thereby allowing interpretation of the underlying physics using critical point theory. This type of quantitative interpretation of the flow structure is crucial for performing vorticity balances on wings and bodies and thereby optimization of overall performance characteristics. Furthermore, for the case of the delta wing at high angle of attack, local control techniques are applied simultaneously at leading and trailing edges of the wing, in order to alter the crucial features of vortex breakdown and subsequent large scale stall. Such control techniques have application to a wide variety of separated flows from wings and cylindrical bodies.
Book Synopsis Static and Dynamic Flow Visualization Studies of Two Double-delta Wing Models at High Angles of Attack by : Feng-Hsi Li
Download or read book Static and Dynamic Flow Visualization Studies of Two Double-delta Wing Models at High Angles of Attack written by Feng-Hsi Li and published by . This book was released on 1992 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis View of a Breakdown by : Norman W. Schaeffler
Download or read book View of a Breakdown written by Norman W. Schaeffler and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
