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Investigation Of Ground Effect On The Wingtip Vortices Generated Behind A Swept And Tapered Wing
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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 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 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 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 Full Scale Visualization of the Wing Tip Vortices Generated by a Typical Agricultural Aircraft by :
Download or read book Full Scale Visualization of the Wing Tip Vortices Generated by a Typical Agricultural Aircraft written by and published by . This book was released on 1980 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Characteristics of Low-aspect-ratio Wings in Close Proximity to the Ground by : Marvin P. Fink
Download or read book Aerodynamic Characteristics of Low-aspect-ratio Wings in Close Proximity to the Ground written by Marvin P. Fink and published by . This book was released on 1961 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Wind-tunnel Investigation of Ground Effect on Wings with Flaps by : Isidore G. Recant
Download or read book Wind-tunnel Investigation of Ground Effect on Wings with Flaps written by Isidore G. Recant and published by . This book was released on 1939 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was conducted in the N.A.C.A. 7- by 10-foot wind tunel to determine the effect of ground proximity on the aerodynamic characteristics of wings equipped with high-lift devices. A rectangular and a tapered wing were tested without flaps, with a split flap, and with a slotted flap. The ground was represented by a flat plate, completely spanning the tunnel and extending a considerable distance ahead and back of the model. The position of the plate was varied from one-half to three chord lengths below the wing.
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 An investigation into the aerodynamics of wings in ground effect by : Jonathan David Chaim Zerihan
Download or read book An investigation into the aerodynamics of wings in ground effect written by Jonathan David Chaim Zerihan and published by . This book was released on 2001 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lift and Pitching Moment Induced on Jet STOVL by the Ground Vortex by : Vearl R. Stewart
Download or read book Lift and Pitching Moment Induced on Jet STOVL by the Ground Vortex written by Vearl R. Stewart and published by . This book was released on 1993 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The data obtained during an investigation of the effects of the ground vortex on a generic wing-body configuration are presented in this report. Circular, rectangular and thrust reverser jets were tested. The tests were conducted in the 14 by 22 foot tunnel at the NASA Langley Research Center. The tests covered a range of heights above the ground, forward velocities, and ground belt speeds.
Book Synopsis An Experimental and Theoretical Investigation of Thick Wings at Various Sweep Angles in and Out of Ground Effect by : John W. Paulson
Download or read book An Experimental and Theoretical Investigation of Thick Wings at Various Sweep Angles in and Out of Ground Effect written by John W. Paulson and published by . This book was released on 1982 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Investigation of the Trailing Vortex System Generated by a Jet-flapped Wing Operating at High Wing Lift Coefficients by : Barnes Warnock McCormick
Download or read book An Investigation of the Trailing Vortex System Generated by a Jet-flapped Wing Operating at High Wing Lift Coefficients written by Barnes Warnock McCormick and published by . This book was released on 1970 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the investigation was to measure the geometry of the trailing vortex generated behind a jet-flapped wing. Such vortices can pose a serious hazard to aircraft that penetrate them. Previous investigations performed on conventional wings indicate that these vortices persist for some time and have maximum tangential velocities which increase linearly with the lift coefficient. As future aircraft may employ high lift devices such as jet-flapped wings, the vortices generated could be even stronger. Two semispan models of a jet-flapped wing were tested in a subsonic wing tunnel. Parameters varied during testing included the jet flap angle, angle of attack, aspect ratio, and jet momentum coefficient. Vortex measurements were obtained using a vortex meter which measured the rotational speed of the fluid within the vortex. Values obtained were numerically integrated to yield the tangential velocity and circulation distributed through the vortex. Experimental results indicate that the maximum tangential velocity increases to a maximum and then decreases with continually increasing jet blowing. At high values of jet blowing, the vortex was found to decay rapidly downstream. (Author).
Book Synopsis Introduction to Aircraft Flight Mechanics by : Thomas R. Yechout
Download or read book Introduction to Aircraft Flight Mechanics written by Thomas R. Yechout and published by AIAA. This book was released on 2003 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on a 15-year successful approach to teaching aircraft flight mechanics at the US Air Force Academy, this text explains the concepts and derivations of equations for aircraft flight mechanics. It covers aircraft performance, static stability, aircraft dynamics stability and feedback control.
Book Synopsis An experimental investigation into the aerodynamic characteristics of a wing, with and without endplates, in ground effect by : P. E. Kumar
Download or read book An experimental investigation into the aerodynamic characteristics of a wing, with and without endplates, in ground effect written by P. E. Kumar and published by . This book was released on 1968 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Theoretical and Experimental Investigation of the Longitudinal Aerodynamics of a Series of Thick Wings In- and Out-of-ground Effect by : John Wilferd Paulson
Download or read book Theoretical and Experimental Investigation of the Longitudinal Aerodynamics of a Series of Thick Wings In- and Out-of-ground Effect written by John Wilferd Paulson and published by . This book was released on 1982 with total page 334 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 Wingtip Vortices and Free Shear Layer Interaction in the Vicinity of Maximum Lift to Drag Ratio Lift Condition by : Muhammad Omar Memon
Download or read book Wingtip Vortices and Free Shear Layer Interaction in the Vicinity of Maximum Lift to Drag Ratio Lift Condition written by Muhammad Omar Memon and published by . This book was released on 2017 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cost-effective air-travel is something everyone wishes for when it comes to booking flights. The continued and projected increase in commercial air travel advocates for energy efficient airplanes, reduced carbon footprint, and a strong need to accommodate more airplanes into airports. All of these needs are directly affected by the magnitudes of drag these aircraft experience and the nature of their wingtip vortex. A large portion of the aerodynamic drag results from the airflow rolling from the higher pressure side of the wing to the lower pressure side, causing the wingtip vortices. The generation of this particular drag is inevitable however, a more fundamental understanding of the phenomenon could result in applications whose benefits extend much beyond the relatively minuscule benefits of commonly-used winglets. Maximizing airport efficiency calls for shorter intervals between takeoffs and landings. Wingtip vortices can be hazardous for following aircraft that may fly directly through the high-velocity swirls causing upsets at vulnerably low speeds and altitudes. The vortex system in the near wake is typically more complex since strong vortices tend to continue developing throughout the near wake region. Several chord lengths distance downstream of a wing, the so-called fully rolled up wing wake evolves into a combination of a discrete wingtip vortex pair and a free shear layer. Lift induced drag is generated as a byproduct of downwash induced by the wingtip vortices. The parasite drag results from a combination of form/pressure drag and the upper and lower surface boundary layers. These parasite effects amalgamate to create the free shear layer in the wake. While the wingtip vortices embody a large portion of the total drag at lifting angles, flow properties in the free shear layer also reveal their contribution to the aerodynamic efficiency of the aircraft. Since aircraft rarely cruise at maximum aerodynamic efficiency, a better understanding of the balance between the lift induced drag (wingtip vortices) and parasite drag (free shear layer) can have a significant impact. Particle Image Velocimetry (PIV) experiments were performed at a) a water tunnel at ILR Aachen, Germany, and b) at the University of Dayton Low Speed Wind Tunnel in the near wake of an AR 6 wing with a Clark-Y airfoil to investigate the characteristics of the wingtip vortex and free shear layer at angles of attack in the vicinity of maximum aerodynamic efficiency for the wing. The data was taken 1.5 and 3 chord lengths downstream of the wing at varying free-stream velocities. A unique exergy-based technique was introduced to quantify distinct changes in the wingtip vortex axial core flow. The existence of wingtip vortex axial core flow transformation from wake-like (velocity less-than the freestream) to jet-like (velocity greater-than the freestream) behavior in the vicinity of the maximum (L/D) angles was observed. The exergy-based technique was able to identify the change in the out of plane profile and corresponding changes in the L/D performance. The resulting velocity components in and around the free shear layer in the wing wake showed counter flow in the cross-flow plane presumably corresponding to behavior associated with the flow over the upper and lower surfaces of the wing. Even though the velocity magnitudes in the free shear layer in cross-flow plane are a small fraction of the freestream velocity (~10%), significant directional flow was observed. An indication of the possibility of the transfer of momentum (from inboard to outboard of the wing) was identified through spanwise flow corresponding to the upper and lower surfaces through the free shear layer in the wake. A transition from minimal cross flow in the free shear layer to a well-established shear flow in the spanwise direction occurs in the vicinity of maximum lift-to-drag ratio (max L/D) angle of attack. A distinctive balance between the lift induced drag and parasite drag was identified. Improved understanding of this relationship could be extended not only to improve aircraft performance through the reduction of lift induced drag, but also to air vehicle performance in off-design cruise conditions.
