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An Investigation Of The Breakdown Of The Leading Edge Vortices On A Delta Wing At High Angles Of Attack
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Book Synopsis An Investigation of the Breakdown of the Leading Edge Vortices on a Delta Wing at High Angles of Attack by : John F. McKernan
Download or read book An Investigation of the Breakdown of the Leading Edge Vortices on a Delta Wing at High Angles of Attack written by John F. McKernan and published by . This book was released on 1983 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Influence of Airfoil Geometry on Delta Wing Leading-edge Vortices and Vortex-induced Aerodynamics at Supersonic Speeds by : Richard M. Wood
Download or read book Influence of Airfoil Geometry on Delta Wing Leading-edge Vortices and Vortex-induced Aerodynamics at Supersonic Speeds written by Richard M. Wood and published by . This book was released on 1992 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of Leading Edge Vortices and Passage to Stall of Nonslender Delta Wings by :
Download or read book An Experimental Investigation of Leading Edge Vortices and Passage to Stall of Nonslender Delta Wings written by and published by . This book was released on 2003 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722866273 Total Pages :86 pages Book Rating :4.8/5 (662 download)
Book Synopsis Visualization of Leading Edge Vortices on a Series of Flat Plate Delta Wings by : National Aeronautics and Space Administration (NASA)
Download or read book Visualization of Leading Edge Vortices on a Series of Flat Plate Delta Wings written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of flow visualization data obtained as part of NASA Grant NAG2-258 is presented. During the course of this study, many still and high speed motion pictures were taken of the leading edge vortices on a series of flat plate delta wings at varying angles of attack. The purpose is to present a systematic collection of photographs showing the state of vortices as a function of the angle of attack for the four models tested. Payne, Francis M. and Ng, T. Terry and Nelson, Robert C. Unspecified Center...
Book Synopsis Separated and Vortical Flow in Aircraft Wing Aerodynamics by : Ernst Heinrich Hirschel
Download or read book Separated and Vortical Flow in Aircraft Wing Aerodynamics written by Ernst Heinrich Hirschel and published by Springer Nature. This book was released on 2020-10-04 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid mechanical aspects of separated and vortical flow in aircraft wing aerodynamics are treated. The focus is on two wing classes: (1) large aspect-ratio wings and (2) small aspect-ratio delta-type wings. Aerodynamic design issues in general are not dealt with. Discrete numerical simulation methods play a progressively larger role in aircraft design and development. Accordingly, in the introduction to the book the different mathematical models are considered, which underlie the aerodynamic computation methods (panel methods, RANS and scale-resolving methods). Special methods are the Euler methods, which as rather inexpensive methods embrace compressibility effects and also permit to describe lifting-wing flow. The concept of the kinematically active and inactive vorticity content of shear layers gives insight into many flow phenomena, but also, with the second break of symmetry---the first one is due to the Kutta condition---an explanation of lifting-wing flow fields. The prerequisite is an extended definition of separation: “flow-off separation” at sharp trailing edges of class (1) wings and at sharp leading edges of class (2) wings. The vorticity-content concept, with a compatibility condition for flow-off separation at sharp edges, permits to understand the properties of the evolving trailing vortex layer and the resulting pair of trailing vortices of class (1) wings. The concept also shows that Euler methods at sharp delta or strake leading edges of class (2) wings can give reliable results. Three main topics are treated: 1) Basic Principles are considered first: boundary-layer flow, vortex theory, the vorticity content of shear layers, Euler solutions for lifting wings, the Kutta condition in reality and the topology of skin-friction and velocity fields. 2) Unit Problems treat isolated flow phenomena of the two wing classes. Capabilities of panel and Euler methods are investigated. One Unit Problem is the flow past the wing of the NASA Common Research Model. Other Unit Problems concern the lee-side vortex system appearing at the Vortex-Flow Experiment 1 and 2 sharp- and blunt-edged delta configurations, at a delta wing with partly round leading edges, and also at the Blunt Delta Wing at hypersonic speed. 3) Selected Flow Problems of the two wing classes. In short sections practical design problems are discussed. The treatment of flow past fuselages, although desirable, was not possible in the frame of this book.
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 Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
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 Controlled Vortical Flow on Delta Wings Through Unsteady Leading Edge Blowing by : National Aeronautics and Space Adm Nasa
Download or read book Controlled Vortical Flow on Delta Wings Through Unsteady Leading Edge Blowing written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-18 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vortical flow over a delta wing contributes an important part of the lift - the so called nonlinear lift. Controlling this vortical flow with its favorable influence would enhance aircraft maneuverability at high angle of attack. Several previous studies have shown that control of the vortical flow field is possible through the use of blowing jets. The present experimental research studies vortical flow control by applying a new blowing scheme to the rounded leading edge of a delta wing; this blowing scheme is called Tangential Leading Edge Blowing (TLEB). Vortical flow response both to steady blowing and to unsteady blowing is investigated. It is found that TLEB can redevelop stable, strong vortices even in the post-stall angle of attack regime. Analysis of the steady data shows that the effect of leading edge blowing can be interpreted as an effective change in angle of attack. The examination of the fundamental time scales for vortical flow re-organization after the application of blowing for different initial states of the flow field is studied. Different time scales for flow re-organization are shown to depend upon the effective angle of attack. A faster response time can be achieved at angles of attack beyond stall by a suitable choice of the initial blowing momentum strength. Consequently, TLEB shows the potential of controlling the vortical flow over a wide range of angles of attack; i.e., in both for pre-stall and post-stall conditions. Lee, K. T. and Roberts, Leonard BLOWING; DELTA WINGS; FLOW DISTRIBUTION; LEADING EDGES; VORTICES; AIRCRAFT MANEUVERS; ANGLE OF ATTACK; MOMENTUM; NONLINEARITY; STABILITY...
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1969 with total page 1090 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of a Device for Controlling the Leading Edge Vortices Ona Delta Wing by : Mohamed Gad-el-Hak
Download or read book Development of a Device for Controlling the Leading Edge Vortices Ona Delta Wing written by Mohamed Gad-el-Hak and published by . This book was released on 1986 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of the Vortex Flow Over Delta and Double-Delta Wings at Low Speed by : N. G. Verhaagen
Download or read book An Experimental Investigation of the Vortex Flow Over Delta and Double-Delta Wings at Low Speed written by N. G. Verhaagen and published by . This book was released on 1983 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel investigation was performed to study, by employing a laserlight-sheet and oil-flow visualization technique, the flow above and behind a sharp-edge 76 deg, delta wing and two sharp-edged double-delta wing models (76/60 and 76/40 deg., kink at midcord). In addition, balance measurements were performed to determine lift, drag and pitching moment. The tests were carried out for angles of attack from 5 to 25 deg. and at a free-stream velocity of 30 m/sec, corresponding to a Reynolds number of 1400000 x 10 to the 6th power, based on centerline chord. Above both double-delta wings a single-branched strake vortex is formed fed by vorticity from the strake leading edge. Downstream of the leading-edge kink a wing vortex is formed which is conjectured to be single-branched at about 5 deg, angle of attack and double branched at angles of 10 deg., an beyond. The flow pattern downstream of the trailing edge of the 76/60 deg. double-delta wing has been observed to be similar to that behind the delta wing. Above the 76/40 deg. double-delta wing breakdown of both the wing and strake vortices took place ahead of the trailing edge. (Author).
Book Synopsis A Collection of Technical Papers by :
Download or read book A Collection of Technical Papers written by and published by . This book was released on 1983 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Joint Institute for Aeronautics and Acoustics. Joint Institute for Aeronautics and Acoustics Publisher : ISBN 13 : Total Pages :48 pages Book Rating :4.F/5 ( download)
Book Synopsis Experimental Studies of a Delta Wing with Leading Edge Flaps by : Joint Institute for Aeronautics and Acoustics. Joint Institute for Aeronautics and Acoustics
Download or read book Experimental Studies of a Delta Wing with Leading Edge Flaps written by Joint Institute for Aeronautics and Acoustics. Joint Institute for Aeronautics and Acoustics and published by . This book was released on 1987 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Digital Particle Image Velocimetry Investigation of Delta Wing Vortex Flow and Vortex Breakdown by : Jeremy David Wimer
Download or read book A Digital Particle Image Velocimetry Investigation of Delta Wing Vortex Flow and Vortex Breakdown written by Jeremy David Wimer and published by . This book was released on 2003-01-01 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vortical flow over the suction side of a 650 sweep delta wing at high angles of attack is investigated in the University of Washington water tunnel using digital particle image velocimetry (DPIV). The method is first validated and then used to qualitatively and quantitatively describe the development of the leading edge vortex (LEV) both upstream and downstream of vortex breakdown. The circulation and azimuthal velocity profile in the vortex are measured and reveal that the maximum circulation of the LEV increases nearly linearly in the downstream direction up to the point of vortex breakdown. Circulation and velocity measurements in the solid-body rotational part of the LEV core, however, reveal that once the core is formed near the apex of the wing, the circulation there remains constant until just prior to breakdown, and no further vorticity is added to the core from the shear layer. The secondary vortex is found to be the key player in separating the primary vortex core from the shear layer. This model of the flow field contradicts the generally accepted conical nature of delta wing flow. Current vortex breakdown suppression methods are analyzed in light of this new model. A numerical simulation based on the vortex filament method is also used to further the self-induction theory of vortex breakdown.
