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Investigation Of The Ground Effect On Wingtip Vortex Generated By A Rectangular Naca0012 Wing
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Book Synopsis Investigation of the Ground Effect on Wingtip Vortex Generated by a Rectangular NACA0012 Wing by : Anan Lu
Download or read book Investigation of the Ground Effect on Wingtip Vortex Generated by a Rectangular NACA0012 Wing written by Anan Lu and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The two stream-wise counter-rotating wingtip vortices generated behind aircraft and their interactions with the runway have always been a concern to aviation, airport traffic control, and aircraft manufacturers alike. For aircraft flying at constant distance from ground (i.e. Ground Effect Vehicles), the behavior of wake vortices and the lift-induced drag are being investigated as well. It was observed that lift increase and drag reduction are experienced by wings in ground effect. To further understand the phenomenon both qualitatively and quantitatively, the ground effect on the aerodynamics and tip vortex flow of a rectangular wing was investigated experimentally at Re=2.71×10^5. The results showed that there was a large lift increase with reducing ground distance. By contrast, a small drag increase was observed in ground effect except in close ground proximity for which a significant drag decrease appeared. The tip vortex also moved further outboard and upward with reducing ground distance. Near the ground, there was the presence of a corotating ground vortex (produced by the rolling up of the boundary layer developed on the ground surface), leading to an increased vortex strength. In extreme ground proximity, a counterrotating secondary vortex (SV) (induced by the crossflow of the tip vortex), relative to the tip vortex, appeared, which caused a reduced vortex strength and a lowered lift-induced drag, as well as a vortex rebound. The impact of ground effect on the vortex flow properties was also discussed. The lift-induced drag, computed based on the crossflow measurements via the Maskell wake integral method, in ground effect was compared against the inviscid flow predictions and wind tunnel total drag force measurements"--
Book Synopsis Investigation of Ground Effect on the Wingtip Vortices Generated Behind a Swept and Tapered Wing by : Samson Pinto
Download or read book Investigation of Ground Effect on the Wingtip Vortices Generated Behind a Swept and Tapered Wing written by Samson Pinto and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "An experimental study of the effect of ground proximity on wingtip vortices has been conducted for swept and tapered wing with NACA 0015 profile over a stationary flat surface in a subsonic wind tunnel. The spatial growth and development of the vortex system generated by the swept and tapered wing with and without winglet arrangement have also been studied. It has been noted that with the reduction in ground proximity, the vortex system moved outward along the spanwise direction by 20% of the wingspan, and it moved closer to the ground. In close ground proximity, vortex rebound occurred due to a lack of space for movement of the vortex. For ground proximity of 15% root chord, a co-rotating ground vortex has been observed, and at 5% of root chord, a counter-rotating secondary vortex has been noticed. The interaction of these different vortices has led to the change of the shape of the entire vortex system.The calculation of lift-induced drag has also been computed using vw-crossflow measurements in the near wake region. It has been observed that the lift-induced drag decreases with reducing ground distance. At ground proximity of 5% root chord distance, a 20% decrease in lift-induced drag is seen compared to lift-induced drag outside ground effect. Also, with the addition of a 90° winglet, an average decrease of 5% lift-induced drag is seen when compared to the wing without a winglet. The lift coefficient has been estimated using the circulation of the vortex system both inside and outside ground effect. It has been noted that there is a 53% increase in the coefficient of lift at 5% ground proximity compared to the coefficient of lift outside ground effect. It has been found that the trend of coefficient of lift versus the ground distance matches the trend of other wing planforms and increases exponentially as the ground proximity decreases below 10% root chord. It has been concluded that the swept wing with a 90° winglet arrangement has been found to outperform all other arrangements"--
Book Synopsis Jolie Collection de tableaux des 3 ecoles, bronzes curiosités Dessins by :
Download or read book Jolie Collection de tableaux des 3 ecoles, bronzes curiosités Dessins written by and published by . This book was released on 1833 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fluid Vortices written by Sheldon Green and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 905 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). The book can also be recommended as an advanced graduate-level supplementary textbook. The first nine chapters of the book are suitable for a one-term course; chapters 10--19 form the basis for a second one-term course.
Book Synopsis An In-flight Investigation of Ground Effect on a Forward-swept Wing Airplane by :
Download or read book An In-flight Investigation of Ground Effect on a Forward-swept Wing Airplane written by and published by . This book was released on 1989 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Vortex-wall Interactions and Sports-inspired Airfoil Motions by : Sarah Elizabeth Morris
Download or read book Vortex-wall Interactions and Sports-inspired Airfoil Motions written by Sarah Elizabeth Morris and published by . This book was released on 2020 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding vortex-wall interactions has applications in the context of airplane trailing vortices, as wake vortices are an unavoidable by-product of aerodynamic lift. These vortices pose an increased hazard for aircraft at airport takeoffs and landings, as following aircraft flying through a vortex wake can experience dangerous rolling moments. In this work, we use a vortex generator tank and a delta wing in an XY-Towing Tank to study the dynamics of counter-rotating vortex pairs both in and out of ground effect, via PIV and flow visualization. When a vortex pair approaches a ground plane, the boundary layer that forms on the surface between the vortices and the wall separates, generating secondary vorticity and causing the primary vortex pair to ``rebound'' from the wall. Using a vortex generator tank to produce a temporally evolving vortex pair, it is shown that the introduction of perturbations at the ground plane results in earlier localized secondary vorticity generation. This leads to the formation of coherent secondary vortex structures, and an accelerated decay of the primary vortex pair. This passive, ground-based method could be a means to diminish the wake vortex hazard behind aircraft close to the ground. We study also the spatially evolving trailing vortices in the far-wake of a 75 degree leading-edge sweep-angle delta wing, using a novel technique to measure the axial flow in the vortex core. This technique is unaffected by vortex wandering, allowing us to capture axial flow data as close as 0.03 chord-lengths apart. Using this technique, the streamwise velocity profile is captured over 20 chord-lengths downstream of the delta wing, even when the vortex pair is in ground effect. In this thesis, we also study new modes of NACA 0012 airfoil motions using a ``sports-mimetic'' approach, inspired by the bodyweight motions of Olympic sailors as they maneuver their sailboats when racing. Olympic sailors use various unsteady aerodynamic techniques when racing to increase propulsion for their boat. One such technique is for sailors to use bodyweight movements to roll the boat about its longitudinal axis. This motion is used especially when turning in light winds by either ``roll tacking'' (upwind sailing) or ``roll gybing'' (downwind sailing); it is also used in ``sail flicking'' whereby the sailor rolls the boat, flicking the sail periodically. These motions are characterized in on-the-water experiments using a Laser sailboat and a 420 sailboat, equipped with a GPS, IMU, wind sensor and GoPro camera array. We study the underlying vortex dynamics of these maneuvers using these characteristic motions, along with full-scale flow visualization and laboratory experiments. Flow visualization experiments are conducted on Cayuga Lake with an Olympic Laser Sailboat, using an Enola Gaye WP40 smoke grenade to visualize large-scale flow features around the sail.
Download or read book 04-2326 - 04-2434 written by and published by . This book was released on 2004 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Analysis of the Pressures, Forces and Moments Induced by the Ground Vortex Generated by a Single Impinging Jet by : Richard E. Kuhn
Download or read book An Analysis of the Pressures, Forces and Moments Induced by the Ground Vortex Generated by a Single Impinging Jet written by Richard E. Kuhn and published by . This book was released on 1997 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 1981 with total page 1370 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.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781723837005 Total Pages :64 pages Book Rating :4.8/5 (37 download)
Book Synopsis Experimental Study of the Structure of a Wingtip Vortex by : National Aeronautics and Space Adm Nasa
Download or read book Experimental Study of the Structure of a Wingtip Vortex written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-19 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete look at the near-field development and subsequent role-up of a wingtip vortex from a NACA 0015 wing section is investigated. Two separate but equally important surveys of the vortex structure in the region adjacent to the wingtip and approximately one chord length downstream of the trailing edge are performed. The two surveys provide qualitative flow-visualization an quantitative velocity measurement data. The near-field development and subsequent role-up of the vortex structures is strongly influenced by the angle-of-attack and the end-cap treatment of the wing section. The velocity field near the wingtip of the NACA 0015 wing section was measured with a triple-sensor hot wire probe and compared to flow visualization images produced with titanium tetrachloride smoke injection and laser illumination. The flat end-cap results indicate the formation of multiple, relatively strong vortex structures as opposed to the formation of a single vortex produced with the round end-cap. The multiple vortices generated by the flat end-cap are seen to rotate around a common ce te in a helical pattern until they eventually merge into a single vortex. Compared to a non-dimensional loading parameter, the results of the velocity and flow visualization data shows a "jetlike" axial velocity profile for loading parameter values on the order of 0.1 and a "wakelike" profile for much lower loading parameter values.Anderson, Elgin A. and Wright, Christopher T.Langley Research CenterWING TIPS; VORTICES; SUBSONIC WIND TUNNELS; AERODYNAMIC CONFIGURATIONS; AERODYNAMIC CHARACTERISTICS; FLOW VISUALIZATION; ANGLE OF ATTACK; TRAILING EDGES; VELOCITY DISTRIBUTION
Book Synopsis An Investigation of the Effects of Discrete Wing Tip Jets on Wake Vortex Roll Up by : F. T Gilliam (Jr)
Download or read book An Investigation of the Effects of Discrete Wing Tip Jets on Wake Vortex Roll Up written by F. T Gilliam (Jr) and published by . This book was released on 1983 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A water tunnel experiment and a computational flow field model show that discrete wing tip jets can strongly affect the roll up of the wing tip vortex and apparently decrease its rolled up strength at moderate levels of blowing. The key factor in vortex alleviation was the extent of the local flow interactions between the discrete jets and the developing wing tip vortex. Vortex trajectory in both the spanwise and vertical directions was influenced by the jets. An outboard shift of the wing tip vortex indicated that discrete wing tip jets may be able to produce improved wing aerodynamics during cruise flight. The counterrotating pair of vortices generated by a jet in a cross flow were clearly seen in the water tunnel and appeared to be very effective in reducing the intensity of the wing vortex system. Two types of periodic secondary vortices were also observed in the water tunnel for heavy jet blowing. These were spin-off vortices which periodically developed in the rolling up tip vortex but rapidly spun outboard and above the wing; and entrained vortices which was a set of periodic vortices laterally connecting the wing tip vortex to the vortices embedded in the jet. These secondary vortices are oriented such that they will greatly accelerate the spreading of wake vorticity through the vortex stretching term of the Helmholtz equation. This influence was confirmed in the water tunnel tests.
Book Synopsis An Experimental Study of Wing Tip Vortex in the Near Wake of a Rectangular Wing by : Youxin Zheng
Download or read book An Experimental Study of Wing Tip Vortex in the Near Wake of a Rectangular Wing written by Youxin Zheng and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of Interacting Wing-tip Vortex Pairs by : Jeffrey S. Zsoldos
Download or read book An Experimental Investigation of Interacting Wing-tip Vortex Pairs written by Jeffrey S. Zsoldos and published by . This book was released on 1992 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Investigation of the Oswald Wing Efficiency of Rectangular and Tapered Wings in Ground Effect by :
Download or read book Numerical Investigation of the Oswald Wing Efficiency of Rectangular and Tapered Wings in Ground Effect written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation of the Aerodynamics of a Reverse Delta Wing in Ground Effect Using Passive Control by : David Huitema
Download or read book Experimental Investigation of the Aerodynamics of a Reverse Delta Wing in Ground Effect Using Passive Control written by David Huitema and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Wing-in-ground effect craft utilize the lift augmentation and drag reduction experienced by aircraft flying in close proximity to the ground. Several designs use a reverse delta wing with anhedral tips due to improved stability in ground effect, despite the inferior lift generation of this planform limiting its widespread adoption. Also, archived research into reverse delta wings is limited, especially in ground effect. The aerodynamic forces generated by a slender and non-slender reverse delta wing in ground effect was experimentally investigated using force balance measurements in an open return wind tunnel. The impact of anhedral, rear planform cropping and passive control via Gurney flaplike strips was investigated.The results demonstrate that the impact of ground effect on the reverse delta wing was greatest at low angles of attack and ground clearances. Increased lift is in part a result of increased static pressure on the lower surface. Anhedral further increased lift, suggesting the stagnation of high momentum flow beneath the wing resulting in an "air tunnel" like effect and resulting in significant lift increases at low ground clearances and high anhedral angles. The relation between the lift and drag increments in ground effect was found to be approximately linear, with marginal improvement in the lift-to-drag ratio. In the freestream, employment of side-edge strips shifted the lift-curve leftward (induced camber-like effect), resulting from reduced crossflow leakage and increased windward surface pressure. Equipping these strips in ground effect significantly augmented lift with increasing strip height. An increasingly adverse pressure gradient and extension of the side-edge strip beyond the boundary layer led to increased drag with strip height. Rear planform cropping in freestream conditions had a benign impact on aerodynamic forces, while in ground effect increased lift and drag from greater ground proximity, with increased drag suggesting an enhanced disruption of the spanwise vortex filaments. The optimum configuration was found to be a 30% cropped reverse delta wing with 15-degree anhedral, equipped with side-edge strips with height of 4% of the root chord, resulting in significant lift and aerodynamic efficiency improvements alongside weight loss from the cropping. The above findings generally agreed with the results for the non-slender models, with greater force magnitudes observed for the non-slender case. A non-zero lift coefficient was observed at zero incidence for the non-slender wing in ground effect. Further study is required to elucidate the flow mechanisms.The results presented here are first of a kind for a reverse delta wing in ground effect, demonstrating that lift augmentation may be achieved on reverse delta wings operating in ground effect through the utilization of passive control. These results provide benchmark data for further studies on reverse delta wings in and out of ground effect." --
Book Synopsis Water Tunnel Investigation of the Vortex Dynamics of Periodically Pitched Wings by : Michael David
Download or read book Water Tunnel Investigation of the Vortex Dynamics of Periodically Pitched Wings written by Michael David and published by . This book was released on 1988 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vortex structure above semi-span wings was investigated in the AFFDL's 24-inch water tunnel to determine the effects of periodic pitching using a saw-tooth motion. Each of the six wings was pitched about the mid-chord at nondimensional upstroke rates ranging from 0.05 to 0.30 and down-stroke rates from 0.025 to 0.600 at tunnel flow rates of 0.6 to 3.6 in/sec. Visualization of the vortices obtained through dye injection from the models was recorded using both high speed and 3/4-in. standard speed video systems. Digitized data from the high speed system provided trend data which showed the saw-tooth motion caused a hysteresis effect on the vortex breakdown location for the swept wings where during the upstroke the vortex would burst further aft than during the down-stroke. In addition, comparison of two 65-deg sweep wings with different cross sections (flat plate and NACA 0012-34) showed a smaller hysteresis effect for the thicker wing. For the rectangular wing, increasing down-stroke rates resulted in higher dynamic stall vortex convection rates. Information was also gathered on the oscillation of static breakdown location and the effects on vortex breakdown of tunnel flow velocity. Keywords: Water tunnels, Dynamic stall, Pitching wing, Vortex breakdown. Theses. (EDC).
Book Synopsis Exploratory Investigation of Factors Affecting the Wing Tip Vortex by : James Scheiman
Download or read book Exploratory Investigation of Factors Affecting the Wing Tip Vortex written by James Scheiman and published by . This book was released on 1972 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
