Journal articles: 'Winglets'

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Pratiwi, Henny. "THE EFFECTS OF ANGLE OF ATTACK, REYNOLD NUMBERS AND WINGLET STRUCTURE ON THE PERFORMANCE OF CESSNA 172 SKYHAWK." Angkasa: Jurnal Ilmiah Bidang Teknologi 10, no. 1 (2018): 61. http://dx.doi.org/10.28989/angkasa.v10i1.206.

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This research aims to investigate the effects of angle of attack, Reynold numbers and winglet structure on the performance of Cessna 172 Skyhawk aircraft with winglets variation design. Winglets improve efficiency by diffusing the shed wingtip vortex, which reducing the drag due to lift and improving the wing’s lift over drag ratio. In this research, the specimens are the duplicated of Cesnna 172 Skyhawk wing with 1:40 ratio made of balsa wood. There are three different winglet designs that are compared with the one without winglet. The experiments are conducted in an open wind tunnel to measure the lift and drag force with Reynold numbers of 25,000 and 33,000. It can be concluded that the wings with winglets have higher lift coefficient than wing without winglet for both Reynold numbers. It was also found that all wings with winglets have higher lift-to-drag ratio than wings without winglet where the blended 45o cant angle has the highest value.

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de Mattos, Bento Silva, Paulo Jiniche Komatsu, and Jesuíno Takachi Tomita. "Optimal wingtip device design for transport airplane." Aircraft Engineering and Aerospace Technology 90, no. 5 (2018): 743–63. http://dx.doi.org/10.1108/aeat-07-2015-0183.

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Purpose The present work aims to analyze the feasibility of wingtip device incorporation into transport airplane configurations considering many aspects such as performance, cost and environmental impact. A design framework encompassing optimization for wing-body configurations with and without winglets is described and application examples are presented and discussed. Design/methodology/approach modeFrontier, an object-oriented optimization design framework, was used to perform optimization tasks of configurations with wingtip devices. A full potential code with viscous effects correction was used to calculate the aerodynamic characteristics of the fuselage–wing–winglet configuration. MATLAB® was also used to perform some computations and was easily integrated into the modeFrontier frameworks. CFD analyses of transport airplanes configurations were also performed with Fluent and CFD++ codes. Findings Winglet provides considerable aerodynamic benefits regarding similar wings without winglets. Drag coefficient reduction in the order of 15 drag counts was achieved in the cruise condition. Winglet also provides a small boost in the clean-wing maximum lift coefficient. In addition, less fuel burn means fewer emissions and contributes toward preserving the environment. Practical implications More efficient transport airplanes, presenting considerable lower fuel burn. Social implications Among other contributions, wingtip devices reduce fuel burn, engine emissions and contribute to a longer engine lifespan, reducing direct operating costs. This way, they are in tune with a greener world. Originality/value The paper provides valuable wind-tunnel data of several winglet configurations, an impact of the incorporation of winglets on airplane design diagram and a direct comparison of two optimizations, one performed with winglets in the configuration and the other without winglets. These simulations showed that their Pareto fronts are clearly apart from each other, with the one from the configuration with winglets placed well above the other without winglets. The present simulations indicate that there are always aerodynamic benefits present regardless the skeptical statements of some engineers. that a well-designed wing does not need any winglet.

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Shyu, Jin-Cherng, and Jhao-Siang Jheng. "Heat Transfer Enhancement of Plate-Fin Heat Sinks with Different Types of Winglet Vortex Generators." Energies 13, no. 19 (2020): 5219. http://dx.doi.org/10.3390/en13195219.

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Because the delta winglet in common-flow-down configuration has been recognized as an excellent type of vortex generators (VGs), this study aims to experimentally and numerically investigate the thermo-hydraulic performance of four different forms of winglet VGs featuring sweptback delta winglets in the channel flow in the range 200 < Re < 1000. Both Nusselt number and friction factor of plate-fin heat sinks having different forms of winglets, including delta winglet pair (DWP), rectangular winglet pair (RWP), swept delta winglet pair (SDWP), and swept trapezoid winglet pair (STWP), were measured in a standard wind tunnel without bypass in this study. Four rows of winglets with in-line arrangement were punched on each 10-mm-long, 0.2-mm-thick copper plate, and a total of 16 pieces of copper plates with spacing of 2 mm were fastened together to achieve the heat sink. The projected area, longitudinal and winglet tip spacing, height and angle of attack of those winglets were fixed. Besides that, three-dimensional numerical simulation was also performed in order to investigate the temperature and fluid flow over the plate-fin. The results showed that the longitudinal, common-flow-down vortices generated by the VGs augmented the heat transfer and pressure drop of the heat sink. At airflow velocity of 5 m/s, the heat transfer coefficient and pressure drop of plain plate-fin heat sink were 50.8 W/m2·K and 18 Pa, respectively, while the heat transfer coefficient and the pressure drop of heat sink having SDWP were 70.4 W/m2·K and 36 Pa, respectively. It was found that SDWP produced the highest thermal enhancement factor (TEF) of 1.28 at Re = 1000, followed by both RWP and STWP of similar TEF in the range 200 < Re < 1000. The TEF of DWP was the lowest and it was rapidly increased with the increase of airflow velocity.

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Guerrero, Joel, Marco Sanguineti, and Kevin Wittkowski. "CFD Study of the Impact of Variable Cant Angle Winglets on Total Drag Reduction." Aerospace 5, no. 4 (2018): 126. http://dx.doi.org/10.3390/aerospace5040126.

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Winglets are commonly used drag-reduction and fuel-saving technologies in today’s aviation. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving fuel efficiency and aircraft performance. Traditional winglets are designed as fixed devices attached at the tips of the wings. However, because they are fixed surfaces, they give their best lift-induced drag reduction at a single design point. In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different angle-of-attack values. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle in the performance of a benchmark wing at a Mach number of 0.8395. The results obtained demonstrate that by carefully adjusting the cant angle, the aerodynamic performance can be improved at different angles of attack.

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Guerrero, J. E., M. Sanguineti, and K. Wittkowski. "Variable cant angle winglets for improvement of aircraft flight performance." Meccanica 55, no. 10 (2020): 1917–47. http://dx.doi.org/10.1007/s11012-020-01230-1.

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Abstract Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

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Yang, Yang, Siddharth Koushik Mohanakrishnan, David S.-K. Ting, and Steve Ray. "DELTA WINGLETS FOR ENHANCING SOLAR ENERGY: TURBULENT STRAIN RATE-HEAT CONVECTION RELATIONSHIP." Journal of Green Building 16, no. 2 (2021): 97–114. http://dx.doi.org/10.3992/jgb.16.2.97.

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ABSTRACT Delta winglets are an effective means for enhancing heat exchange and thus the performance of renewable energy technologies, including solar energy. A pair of 0.1 mm thick, 15 mm high (h) and 30 mm long aluminum winglets separated with transversal spacing, s, of 2h, h and 0 were scrutinized in a closed-loop wind tunnel at a Reynolds number based on h of 6300. The turbulent flow was characterized using a 3D hotwire probe, and the heat convection augmentation was quantified in terms of the normalized Nusselt number (Nu/Nu0), indicating the heat transfer improvement compared to the reference case without the winglets. The interaction of the organized counter-rotational vortices intensifies and they become indiscernible at s = 0. The peak strain rate at 10h downstream increased from 390 s–1, to 478 s–1, to 514 s–1, when the spacing decreased from 2h to h to 0, respectively. The zero-spaced winglet pair provided the largest Nu/Nu0, of around 1.21, at X/h = 10 and Y/h = 0, approximately 21% higher than that of 2h-spaced winglet pair, due to the strongest strain rate and the absence of upwash flow. On the other hand, the 2h-spaced winglet pair provided the largest span-averaged Nu/Nu0, which is of practical significance.

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Suwannapan, Supattarachai, Panuwat Hoonpong, Pongjet Promvonge, Sirisawat Juengjaroennirachon, and Monsak Pimsarn. "Experimental Study on Flow Friction and Heat Transfer in a Square-Duct Heat Exchanger with Winglet Turbulators." Advanced Materials Research 931-932 (May 2014): 1183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.1183.

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The paper presents an experimental study on airflow friction and heat transfer behaviors in a heat exchanger square-duct fitted with winglet turbulators. The experiments are carried out by varying the airflow rate in terms of Reynolds number from 4000 to 25,000. The winglets were mounted in tandem with three attack angles (α=30o, 45o and 60o), two winglet-pitch to duct-height ratios, (called pitch ratio, PR=P/H=1.0 and 1.5) and a single winglet-to duct-height ratio, (called blockage ratio, BR=e/H=0.2). Effects of the winglet parameters on heat transfer and pressure loss in terms of Nusselt number and friction factor are investigated. The experimental result reveals that the application of the winglets provides considerably higher heat transfer and pressure loss values than the smooth duct alone. The winglet at α=60o and PR=1 gives the maximum heat transfer and pressure loss but the one at α = 30o and PR=1.5 yields the highest thermal enhancement factor of about 1.49 at the lowest Reynolds number.

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Wu, Wanyang, and Jingjun Zhong. "Experimental investigation of the influence on compressor cascade characteristics at high subsonic speed with pressure surface tip winglets." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 235, no. 6 (2021): 1257–71. http://dx.doi.org/10.1177/0957650921990198.

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To investigate the influence of tip winglets on the tip leakage flow in a compressor cascade with different incidences, the experimental measurement combined with numerical simulation are used to study the conventional cascade and cascades with three different pressure surface tip winglets at five incidences of −6°, −3°, 0°, +3° and +6°. The results indicate that three different tip winglets at five incidences all restrain the occurrence of leakage flow, delay the mixing of leakage flow and the mainstream, change the formation path of leakage vortex and weaken its intensity, reduce the flow loss and improve the uniformity of flow field. The sensitivity of the flow field to variable incidences is reduced. The optimization degree of the flow field is proportional to the width of the blade tip winglet. The improvements are more obvious at positive angles. When the incidence reaches +6°, the flow loss is reduced by 12.4%.

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Bera, Kamal K., and Naresh K. Chandiramani. "Aeroelastic flutter control of a bridge using rotating mass dampers and winglets." Journal of Vibration and Control 26, no. 23-24 (2020): 2185–92. http://dx.doi.org/10.1177/1077546320915341.

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Flutter control of a bridge deck section using a combination of aerodynamic and mechanical measures, that is controllable winglets and rotating mass dampers, is considered. Deck and winglets are considered as flat plates for their aerodynamics. Self-excited wind forces are represented in the time domain using the Scanlan–Tomko model with Roger’s rational function approximation for flutter derivatives. Winglet rotation relative to the deck is the control input generated by the variable-gain output feedback controller that uses vertical and torsional displacements of the deck as measured outputs. Control using winglets enhances the critical speed to twice the uncontrolled flutter speed. Further attenuation of vertical response is obtained by using rotating mass dampers configured to provide only a resultant vertical force due to counter-rotating unbalanced masses. The rotors are driven at a constant angular speed, and start–stop criteria are applied. This generates additional vertical force on the deck that is mostly out of phase with its vertical velocity. It yields better control than the damper operated in a continuous rotation mode for a fixed number of cycles. A maximum reduction of 15% in root mean square vertical response is obtained when compared with control using winglets only.

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Семків, Тарас Олегович, and Дмитро Миколайович Зінченко. "Adaptive winglets." MECHANICS OF GYROSCOPIC SYSTEMS, no. 35 (May 15, 2018): 75–81. http://dx.doi.org/10.20535/0203-3771352018143891.

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Khalafallah, Mohamed G., Abdelnaby M. Ahmed, and Mohamed K. Emam. "The effect of using winglets to enhance the performance of swept blades of a horizontal axis wind turbine." Advances in Mechanical Engineering 11, no. 9 (2019): 168781401987831. http://dx.doi.org/10.1177/1687814019878312.

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One of the recent methods to improve the performance of horizontal axis wind turbine is to attach a winglet at the tip of the blade of these turbines. Winglets reduce the effect of vortex flow at the blade tip and thus improve the performance of the blade. This article presents a parametric study using the computational fluid dynamics (CFD) modeling to investigate the capability of a winglet to increase the turbine power of swept blades as well as straight blades of a horizontal axis wind turbine. The effects of winglet direction, cant angle, and twist angle are studied for two winglet orientations: upstream and downstream directions. The numerical simulation was performed using ANSYS Fluent computational fluid dynamics code. A three-dimensional computational domain, cylindrical rotationally periodic, was used in the computations. The k-ω shear-stress transport turbulence model was adopted to demonstrate turbulence in the flow. Results show that horizontal axis wind turbine with winglet and sweep could enhance more power compared to their equivalent straight or swept blade. The best improvement in the coefficient of power is 4.39% at design tip speed ratio. This is achieved for downstream swept blades with winglets pointing in the upstream direction and having cant and twist angles of 40° and 10°, respectively.

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Yan, Bowen, Ke Li, Shaopeng Li, Guowei Qian, and Yi Hui. "Short-Term Response of a Bridge-Winglet Sectional Model under Active Flutter Control." International Journal of Structural Stability and Dynamics 20, no. 08 (2020): 2050084. http://dx.doi.org/10.1142/s0219455420500844.

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Active winglets, with a manually controlled attitude angle, can take advantage of the self-excited force to suppress the flutter tendency of a bridge girder. Previous studies mostly focused on the effectiveness and robustness under long-term closed-loop control. However, the deck-winglet system’s short-term response, due to the memory effect of the aerodynamic force, is of concern. A bridge sectional model with active winglets was developed to investigate this problem. Experiments with different phase shifts between the members of the winglet pair were carried out in a wind tunnel. We found that the influence residue of an instantaneous change of the control pattern lasted about three pitching cycles, indicating that a large control interval was acceptable for practical applications. A theoretical relationship between the control effect and control phase was derived to explain the results of the open-loop control. The system responses under different control intervals were analyzed by the closed-loop control, demonstrating that a large control interval was acceptable if some time-consuming algorithms are used in a practical bridge’s flutter control operation.

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Krebs, A. Travis, and B. Dr Götz Bramesfeld. "Using an optimisation process for sailplane winglet design." Aeronautical Journal 120, no. 1233 (2016): 1726–45. http://dx.doi.org/10.1017/aer.2016.83.

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ABSTRACTA multi-objective optimisation process is used to design winglets for a high-performance sailplane. The primary optimisation objective is to maximise the average cross-country speed over a range of thermal strengths. Additional contributions to the cost functions are the limitation of the total drag during high-speed cruise and the additional root bending moment due to the winglet. Rather than being a pure design study, the purpose of the herein presented study is to demonstrate that a multi-objective optimisation approach is a suitable and efficient alternative to the more traditional, experienced-based design approach. The flight performance of the winglet designs are evaluated using a higher-order potential flow method. Results of the optimisation are hand-selected for further analysis. They are compared to a traditionally designed winglet for the same aircraft, designed with similar objectives in mind. The chosen final designs provide an increase in average cross-country speed of 1.5% at lower thermal strengths and 0.4% at higher thermal strengths when compared to the traditional design. When approximating the effects of trim drag due to wing loading and static margin, these performance gains fall to 0.6% and 0.1% respectively, more closely matching the performance of the traditionally designed winglet. The final designs, along with the traditional design, provide performance benefits across all airspeeds of the flight envelope of the base aircraft without winglets.

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Gatto, A., P. Bourdin, and M. I. Friswell. "Experimental Investigation into the Control and Load Alleviation Capabilities of Articulated Winglets." International Journal of Aerospace Engineering 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/789501.

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An experimental investigation into the real-time flow and control characteristics of a flying wing with articulated winglets is described in this paper. The philosophy of the concept centres around the use of active, in-flight adjustment of each wing's winglet dihedral angle, both as a primary means of aircraft roll control (single winglet actuation) and though smaller equal and simultaneous winglet deflections, tailor and alleviate main wing load. Results presented in this paper do provide good evidence of the concept's ability to adequately perform both tasks, although for the current chosen wing/winglet configuration, roll control authority was unable to achieve, per unit of control surface deflection, the same level of performance set by modern aileron-based roll control methodologies.

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Tongyote, Pattarapan, Pongjet Promvonge, Nattawoot Depaiwa, and Withada Jedsadaratanachai. "Thermal performance in a tubular heat exchanger with deltawinglets." MATEC Web of Conferences 192 (2018): 02062. http://dx.doi.org/10.1051/matecconf/201819202062.

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The paper presents an experimental heat transfer enhancement study in a tubular heat exchanger fitted with delta-winglets. The experimental work was conducted by varying the airflow rate in the test tube having a constant wall heat-flux for turbulent regime, Reynolds number (Re) from 5200 to 23,000. Effects of three pitch ratios (PR=P/D=1.5, 2.0 and 3.0) and two attack angles, α = 45° and 60°, of the winglets at a single blockage ratio (BR=b/D = 0.15) on thermal characteristics are examined. The experimental results show that the winglet-inserted tube yields, respectively, the heat transfer, friction factor and thermal performance in the form of TEF around 1.99–4.08, 4.9–14.3 times higher than the plain tube and 0.85–1.85, depending on the operating condition.

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Dimino, Ignazio, Giovanni Andreutti, Frédéric Moens, Federico Fonte, Rosario Pecora, and Antonio Concilio. "Integrated Design of a Morphing Winglet for Active Load Control and Alleviation of Turboprop Regional Aircraft." Applied Sciences 11, no. 5 (2021): 2439. http://dx.doi.org/10.3390/app11052439.

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Aircraft winglets are well-established devices that improve aircraft fuel efficiency by enabling a higher lift over drag ratios and lower induced drag. Retrofitting winglets to existing aircraft also increases aircraft payload/range by the same order of the fuel burn savings, although the additional loads and moments imparted to the wing may impact structural interfaces, adding more weight to the wing. Winglet installation on aircraft wing influences numerous design parameters and requires a proper balance between aerodynamics and weight efficiency. Advanced dynamic aeroelastic analyses of the wing/winglet structure are also crucial for this assessment. Within the scope of the Clean Sky 2 REG IADP Airgreen 2 project, targeting novel technologies for next-generation regional aircraft, this paper deals with the integrated design of a full-scale morphing winglet for the purpose of improving aircraft aerodynamic efficiency in off-design flight conditions, lowering wing-bending moments due to maneuvers and increasing aircraft flight stability through morphing technology. A fault-tolerant morphing winglet architecture, based on two independent and asynchronous control surfaces with variable camber and differential settings, is presented. The system is designed to face different flight situations by a proper action on the movable control tabs. The potential for reducing wing and winglet loads by means of the winglet control surfaces is numerically assessed, along with the expected aerodynamic performance and the actuation systems’ integration in the winglet surface geometry. Such a device was designed by CIRA for regional aircraft installation, whereas the aerodynamic benefits and performance were estimated by ONERA on the natural laminar flow wing. An active load controller was developed by PoliMI and UniNA performed aeroelastic trade-offs and flutter calculations due to the coupling of winglet movable harmonics and aircraft wing bending and torsion.

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O’Brien, James E., and Manohar S. Sohal. "Heat Transfer Enhancement for Finned-Tube Heat Exchangers With Winglets." Journal of Heat Transfer 127, no. 2 (2005): 171–78. http://dx.doi.org/10.1115/1.1842786.

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This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51×10−3 to 14.0×10−3kg/s. These flow rates correspond to a duct-height Reynolds number range of 670–6300 with a duct height of 1.106 cm and a duct width-to-height ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a delta-winglet pair. Comparisons of local and average heat transfer distributions for the circular tube with and without winglets are provided. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement associated with the deployment of the winglets with the circular cylinder. At the lowest Reynolds numbers (which correspond to the laminar operating conditions of existing geothermal air-cooled condensers), the enhancement level is nearly a factor of 2. At higher Reynolds numbers, the enhancement level is close to 50%.

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Parra Peñuela, Héctor, William Gómez Rivera, and Hernán Cerón. "Aerodynamic evaluation with cfd of tip devices in blade for wind turbine." BISTUA REVISTA DE LA FACULTAD DE CIENCIAS BASICAS 17, no. 3 (2019): 70. http://dx.doi.org/10.24054/01204211.v3.n3.2019.3567.

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La región de la punta en las aspa de un rotor eólico se presenta el fenómeno de arrastre inducido, el cual disminuye la eficiencia aerodinámica de la turbina e incrementa los esfuerzos sobre la estructura. En este trabajo, se analizan computacionalmente (CFD) diferentes dispositivos de punta de aspa, con base en aplicaciones similares como Winglets, Split-Tips, Tip-Tanks, como alternativa de mejora de la aerodinámica. El Reynolds utilizado fue de Re =140000 y modelo RANS de turbulencia K-e, el ángulo de ataque (alfa) fue variado desde -25° hasta 25°. El análisis de los resultados mostró, respecto al aspa con punta base (sin modificación), incremento porcentual del coeficiente de sustentación (CL) así: Split-Tips = 3% Winglet = 4.6%, la punta tipo Tip-Tank no presentó mejora apreciable, La intensidad del vórtice de punta de aspa también mostró relación directa (incremento/disminución) cuando fue comparado con la variación del CD. Palabras clave: CFD, Punta de aspa, Vórtices, Winglets, HAWT.

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Khosravi, Shahriar, and David W. Zingg. "Aerostructural Perspective on Winglets." Journal of Aircraft 54, no. 3 (2017): 1121–38. http://dx.doi.org/10.2514/1.c033914.

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Eppler, R. "Induced drag and winglets." Aerospace Science and Technology 1, no. 1 (1997): 3–15. http://dx.doi.org/10.1016/s1270-9638(97)90019-5.

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Ahmed, Noor A., and K. J. Netto. "Computer Aided Design and Manufacture of a Novel Vertical Axis Wind Turbine Rotor with Winglet." Applied Mechanics and Materials 607 (July 2014): 581–87. http://dx.doi.org/10.4028/www.scientific.net/amm.607.581.

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In this paper the computer aided design and manufacture of a rot with winglet for performance enhancement of a vertical axis wind turbine is presented. Both computer numerical control milling and rapid prototyping have been used in the manufacture of the rotor. The rotor was then tested for performance using the large wind tunnel of the Aerodynamics laboratory of University of New South Wales. The results show substantial improvement of the rotor with the winglets installed.

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G., Prasad, Ramesh M., and Rajasekar K. "Numerical Investigation on Effect of Multiple Winglets for Wind Turbine Applications." International Journal of Engineering & Technology 7, no. 4.5 (2018): 450. http://dx.doi.org/10.14419/ijet.v7i4.5.20204.

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The present article is an effort to examine the potential of multiple winglets to reduce the induced drag of the aerodynamic surface. The advantages of using multiple winglets include reduction of induced drag, increased L/D and improved performance of the Wind turbine. Computational Fluid Dynamics is utilized as to approach the effects of multiple winglets with NACA 24012 airfoil section for untwisted, rectangular wing. The testing of configurations is done at Reynolds number 290,000. FLUENT solver incorporated in ANSYS used for the numerical investigation of the steady flow over the wing. A substantial improvement in lift curve slope occurs with dihedral spread of the winglets. The dihedral spread also distributes the tip vortices.

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Phan, Duc-Huynh. "Passive Winglet Control of Flutter and Buffeting Responses of Suspension Bridges." International Journal of Structural Stability and Dynamics 18, no. 05 (2018): 1850072. http://dx.doi.org/10.1142/s0219455418500724.

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The passive control using winglets has been considered to be an alternative solution for control of flutter and buffeting responses of long suspension bridges. This method is aimed at not only developing lightweight, reduced-cost stiffening girders without adding stiffness for aerodynamic stability, but also avoiding problems from malfunctions caused by the control and energy supply systems of active control devices by winglets. This paper presented a mechanically controlled approach using the winglets, for which a two-dimensional bridge deck model was numerically and experimentally studied. In addition, numerical research on the flutter and buffeting passive control of a 3000[Formula: see text]m span suspension bridge was carried out. The result showed that the flutter speed of the suspension bridge increases, whereas the buffeting response decreases, through the implementation of the winglets.

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Sclavounos, Paul D., and Yifeng Huang. "Rudder Winglets on Sailing Yachts." Marine Technology and SNAME News 34, no. 03 (1997): 211–32. http://dx.doi.org/10.5957/mt1.1997.34.3.211.

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During the defender round robins of the 1995 America's Cup, the yacht Young America featured a pair of rudder winglets. Their raison d'etre was to improve the vessel rough water performance, and in particular reduce her added resistance in waves. This article presents the background analysis which leads to the conclusion that rudder winglets may improve appreciably the seakeeping performance of a sailing yacht. The seakeeping method used to study the rough water performance of America3 in 1992 and Young America in 1995 is reviewed along with the fluid dynamics governing the generation of thrust by oscillating wingswings. The effect of winglets upon the yacht seakeeping is considered, the mechanisms contributing to the reduction of the yacht added resistance are identified and the effect of rudder, bulb and bow winglets is studied.

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Tiggelbeck, St, N. K. Mitra, and M. Fiebig. "Comparison of Wing-Type Vortex Generators for Heat Transfer Enhancement in Channel Flows." Journal of Heat Transfer 116, no. 4 (1994): 880–85. http://dx.doi.org/10.1115/1.2911462.

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Longitudinal vortices can be generated in a channel flow by punching or mounting small triangular or rectangular pieces on the channel wall. Depending on their forms, these vortex generators (VG) are called delta wing, rectangular wing, pair of delta winglets, and pair of rectangular winglets. The heat transfer enhancement and the flow losses incurred by these four basic forms of VGs have been measured and compared in the Reynolds number range of 2000 to 9000 and for angles of attack between 30 and 90 deg. Local heat transfer coefficients on the wall have been measured by liquid crystal thermography. Results show that winglets perform better than wings and a pair of delta winglets can enhance heat transfer by 46 percent at Re=2000 to 120 percent at Re=8000 over the heat transfer on a plate.

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Dimino, Ignazio, Federico Gallorini, Massimiliano Palmieri, and Giulio Pispola. "Electromechanical Actuation for Morphing Winglets." Actuators 8, no. 2 (2019): 42. http://dx.doi.org/10.3390/act8020042.

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As a key enabler for future aviation technology, the use of servo electromechanical actuation offers new opportunities to transition innovative structural concepts, such as biomimicry morphing structures, from basic research to new commercial aircraft applications. In this paper, the authors address actuator integration aspects of a wing shape-changing flight surface capable of adaptively enhancing aircraft aerodynamic performance and reducing critical wing structural loads. The research was collocated within the Clean Sky 2 Regional Aircraft Demonstration Platform (IADP) and aimed at developing an adaptive winglet concept for green regional aircraft. Finite Element-based tools were employed for the structural design of the adaptive device characterized by two independent movable tabs completely integrated with a linear direct-drive actuation. The structural design process was addressed in compliance with the airworthiness needs posed by the implementation of regional airplanes. Such a load control system requires very demanding actuation performance and sufficient operational reliability to operate on the applicable flight load envelope. These requirements were met by a very compact direct-drive actuator design in which the ball recirculation device was integrated within the screw shaft. Focus was also given to the power-off electric brake necessary to block the structure in a certain position and dynamically brake the moveable surface to follow a certain command position during operation. Both the winglet layout static and dynamic robustness were verified by means of linear stress computations at the most critical conditions and normal mode analyses, respectively, with and without including the integrated actuator system.

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Quraishi, Mohd Mohiuddin, Mohd Abdul Razakh, and Shivasri Chithaluri. "Design and CFD Analysis of Parametric Winglets." SIJ Transactions on Advances in Space Research & Earth Exploration 4, no. 2 (2016): 7–14. http://dx.doi.org/10.9756/sijasree/v4i2/04010020101.

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Raja, Bino Prince D., G. Ramanan, and Diju G. Samuel. "Computational Analysis of Blended Winglet Model Performance by Varying Cant Angle." Journal of Computational and Theoretical Nanoscience 16, no. 2 (2019): 467–71. http://dx.doi.org/10.1166/jctn.2019.7752.

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This work focuses on structural modeling and analysis of aircraft winglet control surfaces. In aerodynamic engineering, reducing drag is an important challenge. To reduce drag a fin device that is placed vertically in the angle set in the wing of the plane. Winglet design reduces fuel consumption by reducing the drag of the aircraft and will make the aircraft more stable during the flight, will also give the aircraft engine more time to reduce the load on the engine thrust life. The goal is to design and simulate a winglet aircraft model using software such as CATIA V5-which is used to build fin models and ANSYS CFX solver is used to test and simulate model fins. With winglets without fins it analyzes change the inclination angles, the results are compared and plotted. Fins are an important part of an aircraft that reduces the amount of drag and fuel consumption by using less energy while reducing wing vortexes.

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Zhu and Gao. "A Numerical Investigation of a Winglet-Propeller using an LES Model." Journal of Marine Science and Engineering 7, no. 10 (2019): 333. http://dx.doi.org/10.3390/jmse7100333.

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The generation of tip vortex cavitation (TVC) is a common phenomenon in marine propellers. Therefore, it is important to find a way for the effective suppression of TVC. Based on the enlightenment of bionics, a propeller with winglets was numerically investigated by using a large eddy simulation (LES) model and the commercial software STAR-CCM+. Various variables, such as mesh size, number of prism layers, vapor properties and time step, were analyzed using the benchmark MAU5-80 propeller. The open water characteristics calculated for the benchmark propeller were compared with experimental data. The meshes in the region of the tip vortex wake were refined. The power spectral density (PSD) of the thrust coefficient and axial velocity were investigated. The comparison of TVC between the benchmark propeller and the propeller with winglets was studied with the Q-criterion, helicity and volume fraction of the vapor. The strength of the tip vortex wake is weakened by winglets; therefore, the presence of winglets leads to a reduction in vapor volume, which in turn alleviates TVC.

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De Breuker, R., M. Abdalla, and Z. Gürdal. "Design of morphing winglets with the inclusion of nonlinear aeroelastic effects." Aeronautical Journal 115, no. 1174 (2011): 713–28. http://dx.doi.org/10.1017/s0001924000006461.

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Abstract A nonlinear aeroelastic model capable of assessing arbitrary morphing manoeuvres and calculating the associated morphing energy requirement is presented in this paper. The aeroelastic model consists of a close coupling between a corotational beam element, accounting for geometric nonlinearities, and a Weissinger method aerodynamic model, containing the Prandtl-Glauert correction for high-subsonic Mach numbers. The morphing deformations are discretised into three distinct morphing modes; fold morphing, twist morphing, and shear morphing, because of which virtually any morphed shape can be achieved, given a proper distribution of the three modes over the wing. The proposed aeroelastic morphing framework is used to design morphing winglets, and it has been shown that morphing winglets can improve the performance of fixed winglets significantly for regional airliners.

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Yen, S. C., and Frank K. T. Lin. "Exit Flow Field and Performance of Axial Flow Fans." Journal of Fluids Engineering 128, no. 2 (2005): 332–40. http://dx.doi.org/10.1115/1.2169809.

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Flow fields near the exit and the global performance parameters of the various types of axial flow fans are studied with Particle Image Velocimetry and a standard AMCA 210 flow bench. The fans used in this study included the shrouded, shroudless, and winglet-blade types. The velocity vectors, streamlines, vorticity contours, velocity distributions, and performances are presented and discussed. The flow patterns on the radial and axial planes show that a vortex always exists near the exit of the fans at various impeller angles. The experimental results demonstrate that the shrouded fan with winglets has the most stable flow field and the best fan performance.

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Marks, Paul. "‘Morphing’ winglets to boost aircraft efficiency." New Scientist 201, no. 2692 (2009): 22–23. http://dx.doi.org/10.1016/s0262-4079(09)60208-6.

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33

Gall, Peter D., and Hubert C. Smith. "Aerodynamic characteristics of biplanes with winglets." Journal of Aircraft 24, no. 8 (1987): 518–22. http://dx.doi.org/10.2514/3.45470.

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Kuhlman, John M., and Paul Liaw. "Winglets on low-aspect-ratio wings." Journal of Aircraft 25, no. 10 (1988): 932–41. http://dx.doi.org/10.2514/3.45682.

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Gavrilović, Nikola N., Boško P. Rašuo, George S. Dulikravich, and Vladimir B. Parezanović. "Commercial aircraft performance improvement using winglets." FME Transaction 43, no. 1 (2015): 1–8. http://dx.doi.org/10.5937/fmet1501001g.

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Siliang, Du, Zhao Qijun, and Tang Zhengfei. "Numerical Simulation of the Effect of Different Number Leading Edge Winglets on the Fan-Wing Aerodynamic Characteristics." International Journal of Aerospace Engineering 2020 (February 11, 2020): 1–15. http://dx.doi.org/10.1155/2020/8941453.

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The generation of lift and thrust mainly depends on the formation of low-pressure vortices above the arc groove on the leading edge of the Fan-wing, which makes the lift and thrust have a strong coupling relationship. How to decouple and control the lift and thrust is the key to further engineering application of the Fan-wing. Normally, the geometric parameters of the Fan-wing airfoil were determined; the leading edge opening angle has the greatest influence on the aerodynamic performance. Therefore, the method of installing leading edge winglets on the leading edge of a base Fan-wing airfoil was considered to change the opening angle of the leading edge of the Fan-wing. Through numerical simulation, the effects of single, double, and triple leading edge winglets on lift and thrust of the Fan-wing at different installation angles, inflow velocities, and angles of attack were compared and analyzed. The results show that by controlling the angle of the leading edge winglet, not only the lift and thrust of the fan can be improved but also the strength and position of the low-pressure vortices can be controlled, so as to meet the active control requirements of the aerodynamic moment of the Fan-wing, and then the attitude of the Fan-wing aircraft can be controlled.

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Mat Taib, C. F., Abdul Aziz Jaafar, and Salmiah Kasolang. "Numerical Study of Winglet Cant Angle Effect on Wing Performance at Low Reynolds Number." Applied Mechanics and Materials 393 (September 2013): 366–71. http://dx.doi.org/10.4028/www.scientific.net/amm.393.366.

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The study on the effect of winglet shape in wing design has been a focus of many researchers. Nevertheless, the effect of cant angle on the wing performances at low Reynolds number has not been fully explored. This paper describes the effect of a single semi-circular shaped winglet attached with a rectangular wing model to lower the drag without increasing the span of the wing. Aerodynamic characteristics for the rectangular wing (NACA 65-3-218) with and without semi-circular winglets have been studied using STAR CCM+ 4.0. This numerical analysis is based on Finite Volume Approach. Simulations were carried out on the rectangular wing model with and without winglet at aspect ratio of 2.73 and Reynolds number of 0.16 x 10 6 for various angles of attack. From the numerical analysis, wing performance characteristics in terms of lift coefficient CL, drag coefficient CD, and lift-to-drag ratio, CL/CD were obtained. It was found that the addition of a semi-circular winglet has resulted in a larger lift curve slope and higher Lift-to-Drag ratio in comparison with the case of a wing without winglet. Further investigation has revealed that a wing with semi-circular winglet with cant angle of 45 degree has produced the best Lift-to-Drag ratio, CL/CD.

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Min, Jingchun, and Bingqiang Zhang. "Convective mass transfer enhancement in a membrane channel by delta winglets and their comparison with rectangular winglets." Chinese Journal of Chemical Engineering 23, no. 11 (2015): 1755–62. http://dx.doi.org/10.1016/j.cjche.2015.09.006.

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Maughmer, Mark D. "Design of Winglets for High-Performance Sailplanes." Journal of Aircraft 40, no. 6 (2003): 1099–106. http://dx.doi.org/10.2514/2.7220.

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Ramakrishnan, B., K. Durai Karthikeyan, M. Faizur Rahman Nasir, V. Achyuth Yadav, S. Syam Narayanan, and R. Asad Ahamed. "EXPERIMENTAL STUDY OF SINGLE AND MULTI-WINGLETS." Advances and Applications in Fluid Mechanics 19, no. 2 (2016): 247–55. http://dx.doi.org/10.17654/fm019020247.

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Guha, T. K., W. S. Oates, and R. Kumar. "Characterization of piezoelectric macrofiber composite actuated winglets." Smart Materials and Structures 24, no. 6 (2015): 065043. http://dx.doi.org/10.1088/0964-1726/24/6/065043.

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Bourdin, P., A. Gatto, and M. I. Friswell. "Aircraft Control via Variable Cant-Angle Winglets." Journal of Aircraft 45, no. 2 (2008): 414–23. http://dx.doi.org/10.2514/1.27720.

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Wong, W. S., A. Le Moigne, and N. Qin. "Parallel adjoint-based optimisation of a blended wing body aircraft with shock control bumps." Aeronautical Journal 111, no. 1117 (2007): 165–74. http://dx.doi.org/10.1017/s0001924000004425.

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An Euler optimisation for a BWB configuration with winglets incorporating an array of three-dimensional shock control bumps is carried out by employing an efficient adjoint-based optimisation methodology. A high fidelity multi-block grid with over two million grid points is generated to resolve the shape of the 3D shock control bumps, the winglet as well as the overall BWB shape, which are parameterised by over 650 design variables. In order to perform such a large aerodynamic optimisation problem feasibly, the optimisation tools such as the flow solver and the adjoint solver have to be parallelised with a good parallel efficiency. This paper reports the parallel implementation efforts on the adjoint solver; especially on the calculation of the sensitivity derivatives, which has to be looped over the total number of design variables. Results from the optimisation of the wing master sections, winglet aerofoil sections and the three dimensional bumps indicate a significant improvement regarding the aerodynamic performance against the baseline geometry for the given planform layout of the aircraft.

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Ciminello, Monica, Angelo De Fenza, Ignazio Dimino, and Rosario Pecora. "Skin-Spar Failure Detection of a Composite Winglet Using FBG Sensors." Archive of Mechanical Engineering 64, no. 3 (2017): 287–300. http://dx.doi.org/10.1515/meceng-2017-0017.

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Abstract Winglets are introduced into modern aircraft to reduce wing aerodynamic drag and to consequently optimize the fuel burn per mission. In order to be aerodynamically effective, these devices are installed at the wing tip section; this wing region is generally characterized by relevant oscillations induced by flights maneuvers and gust. The present work is focused on the validation of a continuous monitoring system based on fiber Bragg grating sensors and frequency domain analysis to detect physical condition of a skin-spar bonding failure in a composite winglet for in-service purposes. Optical fibers are used as deformation sensors. Short Time Fast Fourier Transform (STFT) analysis is applied to analyze the occurrence of structural response deviations on the base of strain data. Obtained results showed high accuracy in estimating static and dynamic deformations and great potentials in detecting structural failure occurrences.

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Wang, Yu. "Numerical study of hydrodynamics and thermal characteristics of heat exchangers with delta winglets." Thermal Science 24, no. 1 Part A (2020): 325–38. http://dx.doi.org/10.2298/tsci180330254w.

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The comprehensive performance of heat exchangers is represented by the maximum thermal transfer, the minimum pressure loss, and the smallest pumping power. In recent years, the application of longitudinal vortex generators is developed as an effective technique and important research topic, which could increase the heat transfer enhancement of compact heat exchangers. A 3-D CFD numerical simulation is successfully carried out on thermohydraulic characteristics of the fin-and-tube compact heat exchanger with new types of vortex generators. The effects of six different arrangement of delta winglets are studied, which are front-up-rear-down, front-down-rear-up, common-flow-up, and common-flow-down. In addition, there are also different direction of hole position in the same delta winglets arrangement. The investigation of thermal-hydraulic performance is conducted for Reynolds number in the range of 204-2034. The overall and local performance comparisons among the fin with delta winglets and the wavy fin are performed. Then, the comprehensive performance evaluation diagram was adopted to analyze the combined index point of thermal and flow. This study shows that the flow distinction between different fins has a profound influence on the thermal-hydrodynamic performance. The results reveal that the fin with delta winglets can considerably strengthen the thermal efficiency with a moderate pressure loss penalty. The computational results indicate that the average j-factor for the fin with delta wing-lets can be increased up to 41.9% over the baseline case and the corresponding f-factor decreased up to 19.5%. The combination property of front-up-rear-down are better the others at lower Reynolds number, and that of front-down-rear-up are better at higher Reynolds number. Compare with the traditional arrangement (common-flow-up and common-flow-down), The newly designed fin has great effectiveness and uniform performance in the local region.

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Abd, Dalya Adnan, and Anmar Hamed Ali. "Aerodynamic Characteristics Comparison between Spiroid and Blended Winglets." Journal of Engineering 26, no. 4 (2020): 33–46. http://dx.doi.org/10.31026/j.eng.2020.04.03.

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Asai, Keisuke. "Theoretical considerations in the aerodynamic effectiveness of winglets." Journal of Aircraft 22, no. 7 (1985): 635–37. http://dx.doi.org/10.2514/3.45177.

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Seo, Yong Cheol, and Sang Woo Lee. "Aerodynamic losses for squealer tip with different winglets." Journal of Mechanical Science and Technology 33, no. 2 (2019): 639–47. http://dx.doi.org/10.1007/s12206-019-0119-2.

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Mostafa, Suhail, Shyam Bose, Archana Nair, et al. "A parametric investigation of non-circular spiroid winglets." EPJ Web of Conferences 67 (2014): 02077. http://dx.doi.org/10.1051/epjconf/20146702077.

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Guerrero, Joel E., Dario Maestro, and Alessandro Bottaro. "Biomimetic spiroid winglets for lift and drag control." Comptes Rendus Mécanique 340, no. 1-2 (2012): 67–80. http://dx.doi.org/10.1016/j.crme.2011.11.007.

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Journal articles on the topic 'Winglets'

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