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An Experimental Investigation Of Leading Edge Vortical Flow About A Delta Wing During Wing Rock
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Book Synopsis An Experimental Investigation of Leading Edge Vortical Flow about a Delta Wing During Wing Rock by : Michael Denis Nelson
Download or read book An Experimental Investigation of Leading Edge Vortical Flow about a Delta Wing During Wing Rock written by Michael Denis Nelson and published by . This book was released on 1991 with total page 368 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:
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...
Book Synopsis An Experimental Investigation of the Flow Fields about Delta and Double-delta Wings at Low Speeds by : William H. Wentz (Jr.)
Download or read book An Experimental Investigation of the Flow Fields about Delta and Double-delta Wings at Low Speeds written by William H. Wentz (Jr.) and published by . This book was released on 1966 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Discrete-Vortex Method for Studying the Wing Rock of Delta Wings by : Thomas G. Gainer
Download or read book A Discrete-Vortex Method for Studying the Wing Rock of Delta Wings written by Thomas G. Gainer and published by . This book was released on 2002 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Further Experimental Investigations of Delta and Double-delta Wing Flow Fields at Low Speeds by : W. H. Wentz
Download or read book Further Experimental Investigations of Delta and Double-delta Wing Flow Fields at Low Speeds written by W. H. Wentz and published by . This book was released on 1967 with total page 140 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 Video-Based Experimental Investigation of Wing Rock by : Steven Lynn Morris
Download or read book A Video-Based Experimental Investigation of Wing Rock written by Steven Lynn Morris and published by . This book was released on 1989 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research developed a definitive theory on the cause of wing rock. The study was based on dynamic measurements in both a water tunnel and a wind tunnel on a sharp-edged delta wing with an 80 deg. leading-edge sweep angle. Experimental data were compared with analytical results from a mathematical model and a fourth order Runge-Kutta integration. In the water tunnel tests, conducted at alpha = 35 deg. and Reynolds numbers from 30000/ft to 75000/ft, the movement of the leading-edge vortices and the model motion were simultaneously tracked and analyzed using a video-based motion analysis system, ExpertVision. The initial phase of the study validated ExpertVision accuracy using stationary and forced oscillation tests on 70 deg. and 80 deg. delta wings. Vortex trajectory, core velocity, and burst point results from stationary tests were in good agreement with published data. Forced oscillation tests proved that ExpertVision could simultaneously track and analyze the movement of leading-edge vortices and model motion. Wing rock is caused by the dynamic behavior of the leading edge vortices. The alternate lift-off and reattachment of the vortices generate an asymmetry in vortex lift and cause changes in rolling moment that initiate and sustain roll oscillations. Wing rock dynamics were significantly different water tunnel and wind tunnel experiments. Apparent mass terms must be included in the equations of motion when converting water tunnel acceleration data to rolling moment coefficients; with no apparent mass correction, C sub l calculated from accelerations in the water tunnel were about 15 times greater than those from the wind tunnel. Theses. (JHD).
Book Synopsis Analytical and Experimental Investigations of Delta Wings in Incompressible Flow by : Balusu M. Rao
Download or read book Analytical and Experimental Investigations of Delta Wings in Incompressible Flow written by Balusu M. Rao and published by . This book was released on 1976 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theoretical analysis of delta wings in incompressible flow is created by a numerical lifting-surface theory based upon a velocity potential formulation. This theory has been expanded to include spanwise velocity effects and the leading-edge departion associated with delta wings. The numerical technique has made use of both fixed and free wakes. In the fixed-wake model, the analytical results of Brown and Michael have been used to position the leading-edge vortex. In the more refined free-wake model, the leading edge separation was modeled as a discrete number of vortices attached to the leading-edge, which are allowed to align themselves with streamlines. Experimental research included wind tunnel tests to determine the vortex location, vortex burst location, and upper surface pressure distribution on a delta wing, AR = 2, in an oscillatory airstream.
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 Experimental Investigation of the Self-induction Theory of Vortex Breakdown and New Observations in the Transient Development of a Delta Wing Leading Edge Vortex by : Brad R. Thompson
Download or read book Experimental Investigation of the Self-induction Theory of Vortex Breakdown and New Observations in the Transient Development of a Delta Wing Leading Edge Vortex written by Brad R. Thompson and published by . This book was released on 2007 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transient development of the leading edge vortex of a 65-deg sweep delta wing is investigated in water tunnel experiments using flow visualization and particle image velocimetry (PIV) measurements. The experiments were conducted at root chord Reynolds numbers from 0 to 3x10 4. The transient results provide experimental evidence supporting the self-induction theory of vortex breakdown. A core radius based circulation overshoot is discovered and attributed to transient development of the vortex core. The transient leading edge vortex core development indicates an initial conical vortex core along the axial direction that transitions to a cylindrical axial core. A passive device that asymmetrically extends the vortex breakdown location is discovered and the mechanisms describing the extension are proposed.
Book Synopsis Vortex flow and vortex breakdown above a delta wing in high supersonic flow by : Sharon Rose Donohoe
Download or read book Vortex flow and vortex breakdown above a delta wing in high supersonic flow written by Sharon Rose Donohoe and published by . This book was released on 1996 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unsteady Structure of Leading-Edge Vortices on a Delta Wing by :
Download or read book Unsteady Structure of Leading-Edge Vortices on a Delta Wing written by and published by . This book was released on 1994 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this research program was to characterize the unsteady flow structure on wings having swept edges. Wings were subjected to global control, involving motion of the entire wing, and local control, involving perturbations at specified locations on the surface of the wing. New types of experimental facilities and image acquisition and processing techniques have allowed determination of the instantaneous vorticity distributions and streamline patterns of the flow. The occurrence of vortex breakdown and stall and their phase shifts relative to the wing motion and to control at the leading-edges have been interpreted in terms of new flow mechanisms. Delta Wings, Vortex Breakdown, Laser Diagnostics.
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 Numerical Study of Delta Wing Leading Edge Blowing by : David Yeh
Download or read book Numerical Study of Delta Wing Leading Edge Blowing written by David Yeh and published by . This book was released on 1988 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
