Optimal wingtip device design for transport airplane

2018 ◽  
Vol 90 (5) ◽  
pp. 743-763 ◽  
Author(s):  
Bento Silva de Mattos ◽  
Paulo Jiniche Komatsu ◽  
Jesuíno Takachi Tomita
Keyword(s):  
Optimization Design ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
The Other ◽  
Full Potential ◽  
Design Framework ◽  
Viscous Effects ◽  
Content Type ◽  
Fuel Burn ◽  
Cfd Analyses

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.

Solar UAV design framework for a HALE flight

2019 ◽  
Vol 91 (7) ◽  
pp. 927-937
Author(s):  
Hoyon Hwang ◽  
Jaeyoung Cha ◽  
Jon Ahn
Keyword(s):  
User Interfaces ◽  
Minimum Weight ◽  
Lift Coefficient ◽  
Aircraft Design ◽  
Design Framework ◽  
Night Time ◽  
Simple Method ◽  
Content Type ◽  
Aerial Vehicle ◽  
Long Endurance

Purpose The purpose of this paper is to present the development of an optimal design framework for high altitude long endurance solar unmanned aerial vehicle. The proposed solar aircraft design framework provides a simple method to design solar aircraft for users of all levels of experience. Design/methodology/approach This design framework consists of algorithms and user interfaces for the design of experiments, optimization and mission analysis that includes aerodynamics, performance, solar energy, weight and flight distances. Findings The proposed sizing method produces the optimal solar aircraft that yields the minimum weight and satisfies the constraints such as the power balance, the night time energy balance and the lift coefficient limit. Research limitations/implications The design conditions for the sizing process are given in terms of mission altitudes, flight dates, flight latitudes/longitudes and design factors for the aircraft configuration. Practical implications The framework environment is light and easily accessible as it is implemented using open programs without the use of any expensive commercial tools or in-house programs. In addition, this study presents a sizing method for solar aircraft as traditional sizing methods fail to reflect their unique features. Social implications Solar aircraft can be used in place of a satellite and introduce many advantages. The solar aircraft is much cheaper than the conventional satellite, which costs approximately $200-300m. It operates at a closer altitude to the ground and allows for a better visual inspection. It also provides greater flexibility of missions and covers a wider range of applications. Originality/value This study presents the implementation of a function that yields optimized flight performance under the given mission conditions, such as climb, cruise and descent for a solar aircraft.

Unsteady aerodynamic characteristics of a morphing wing

2018 ◽  
Vol 91 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jinwu Xiang ◽  
Kai Liu ◽  
Daochun Li ◽  
Chunxiao Cheng ◽  
Enlai Sha
Keyword(s):  
Lift Coefficient ◽  
Angle Of Attack ◽  
Large Angle ◽  
Unsteady Aerodynamics ◽  
Aerodynamic Characteristics ◽  
Static Case ◽  
Morphing Wing ◽  
Trailing Edge ◽  
Content Type ◽  
Unsteady Aerodynamic

Purpose The purpose of this paper is to investigate the unsteady aerodynamic characteristics in the deflection process of a morphing wing with flexible trailing edge, which is based on time-accurate solutions. The dynamic effect of deflection process on the aerodynamics of morphing wing was studied. Design/methodology/approach The computational fluid dynamic method and dynamic mesh combined with user-defined functions were used to simulate the continuous morphing of the flexible trailing edge. The steady aerodynamic characteristics of the morphing deflection and the conventional deflection were studied first. Then, the unsteady aerodynamic characteristics of the morphing wing were investigated as the trailing edge deflects at different rates. Findings The numerical results show that the transient lift coefficient in the deflection process is higher than that of the static case one in large angle of attack. The larger the deflection frequency is, the higher the transient lift coefficient will become. However, the situations are contrary in a small angle of attack. The periodic morphing of the trailing edge with small amplitude and high frequency can increase the lift coefficient after the stall angle. Practical implications The investigation can afford accurate aerodynamic information for the design of aircraft with the morphing wing technology, which has significant advantages in aerodynamic efficiency and control performance. Originality/value The dynamic effects of the deflection process of the morphing trailing edge on aerodynamics were studied. Furthermore, time-accurate solutions can fully explore the unsteady aerodynamics and pressure distribution of the morphing wing.

scholarly journals Initial development of the hybrid semielliptical-dolphin airfoil

2021 ◽  
pp. 234-234
Author(s):  
Zorana Dancuo ◽  
Ivan Kostic ◽  
Olivera Kostic ◽  
Aleksandar Bengin ◽  
Goran Vorotovic
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Calculation Model ◽  
General Aviation ◽  
The Other ◽  
Aviation Industry ◽  
Initial Development ◽  
Other Hand ◽  
Nose Shape

Iosif Taposu has formulated a mathematical model and generated a family of airfoils whose geometry resembles the dolphin shape. These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. On the other hand, they have not been applied to any commercial general aviation aircraft. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu?s dolphin that would have the same principal geometric characteristics. A CFD calculation model has been established and applied on NACA 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. The same CFD model has been applied on the counterpart Dolphin 2415. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1 ? 0.35 than NACA. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin?s sharp nose. A series of the Dolphin?s leading edge modifications has been investigated, gradually improving its aerodynamics. Finally, version M4, consisting of about 70% of Dolphin?s original rear domain and 30% of the new nose shape, managed to exceed the NACA?s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.

Numerical simulation of flow field around the race car in case

2015 ◽  
Vol 25 (8) ◽  
pp. 1896-1911 ◽  
Author(s):  
Tien Phuc Dang ◽  
Zhengqi Gu ◽  
Zhen Chen
Keyword(s):  
Flow Field ◽  
Design Methodology ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Field Structure ◽  
Navier Stokes ◽  
Stationary Case ◽  
Content Type ◽  
Rans Equations ◽  
Race Car

Purpose – The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition, this paper also illustrates and clarifies the influence of wheel rotation on the aerodynamic characteristics around the race car. Design/methodology/approach – The author uses steady Reynolds-Averaged Navier-Stokes (RANS) equations with the Realizable k-ε model to study model open-wheel race car. Two cases are considered, a rotating wheel and stationary wheel. Findings – The results obtained from the study are presented graphically, pressure, velocity distribution, the flow field structure, lift coefficient (Cl) and drag coefficient (Cd) for two cases and the significant influence of rotating case on flow field structure around wheel and aerodynamic characteristics of race car. The decreases in Cd and Cl values in the rotating case for the race car are 16.83 and 13.25 per cent, respectively, when compared to the stationary case. Originality/value – Understanding the flow field structures and aerodynamic characteristics around the race car in two cases by the steady RANS equations with the Realizable k-ε turbulence model.

Research and selection of MALE wing profile

2019 ◽  
Vol 91 (2) ◽  
pp. 264-271 ◽  
Author(s):  
Cezary Gorniak ◽  
Zdobyslaw Jan Goraj ◽  
Bartosz Olszanski
Keyword(s):  
Wind Tunnel ◽  
Early Stage ◽  
Phase 1 ◽  
Lift Coefficient ◽  
High Volume ◽  
Aerodynamic Characteristics ◽  
Preliminary Design ◽  
Content Type ◽  
Wing Section ◽  
Selection Of

Purpose The purpose of this research is a preliminary selection of wing section, which would be the best suited for PW-100 – a MALE class UAV of 600 kg weight. PW-100 will be used as a testing platform in different institutions such as research institutes, industry research centers or universities of technology (phase 1) to enable the in-flight testing of various on-board systems (mobile radars, thermovision sensors, chemical sensors, antennas, teledetection systems and others). Untypical layout of PW-100 resulted from the plans of further development of this configuration for a military application. Design/methodology/approach Important role in the research described in this paper plays the selection of main wing section to fulfil the preliminary requirements regarding maximum lift coefficient, minimum drag, aerodynamic efficiency etc. Two different wing sections (R1082 and SA19) were tested in wind tunnel, both with flaps deflected at the range of 0°-30°. Experimental measurements were performed in the low turbulence wind tunnel with closed test section of 45 cm × 35 cm. Numerical simulations of the flow around the wing sections were performed using MSES code. Boundary conditions were assumed basing on the typical mission of PW-100 for flight altitude around 9,000 m, speed of 110 km/h what results in Re = 956,000. Findings Lift coefficients obtained from both experimental and numerical methods for single slatted airfoil SA19 are much higher than that of get for Ronch R1082 airfoil. PW-100 aircraft with SA19 airfoils will be able to be trimmed and fly at any altitude up to 9,000 m and with an arbitrary weight up to 600 kg. Aerodynamic characteristics of SA19 remain smoother and more predictable than that of R1082 airfoil. The very promising properties of SA19 airfoil are well known to the authors since the beginning of last decade when PW team worked together with IAI team on CAPECON project and now it was fully confirmed by this research. Practical implications It was confirmed that selection of the proper wing section for the special mission performed by UAV is of the highest importance decision to be taken at the preliminary design phase. Because there is a limited access to the base of technical parameters in many different UAVs classes and the classical analysis of trends cannot be fully applied, the wing section analysis, either experimental or numerical, must be performed. The situation is much worse than in the case of manned aircrafts because most of the modern UAVs are made of carbon or glass fiber, and therefore, there is no chance for analysis of trends. Originality/value This paper presents a very efficient method of assessing the influence of wing section on aircraft performance adopted for MALE class UAV, especially in an early stage of preliminary design process. The assessment is built mainly on three requirements: Maximum 2D lift coefficient for take-off configuration with flap deflected on 20 degrees should be greater than 2.4. Endurance factor CL1.5/CD for loitering conditions (Ma = 0.5 and CD0 = 0.008) should be greater than 110. The relative wing section thickness should be greater/equal than 19 per cent (it is required for high volume fuel tank located in the wings).

Aerodynamic performance improvement of WIG aircraft

2017 ◽  
Vol 89 (1) ◽  
pp. 120-132 ◽  
Author(s):  
Mojtaba Tahani ◽  
Mehran Masdari ◽  
Ali Bargestan
Keyword(s):  
Dihedral Angle ◽  
Twist Angle ◽  
Lift Coefficient ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Sweep Angle ◽  
Content Type ◽  
Ground Clearance ◽  
Geometrical Characteristics

Purpose This paper aims to investigate the aerodynamic characteristics as well as static stability of wing-in-ground effect aircraft. The effect of geometrical characteristics, namely, twist angle, dihedral angle, sweep angle and taper ratio are examined. Design/methodology/approach A three-dimensional computational fluid dynamic code is developed to investigate the aerodynamic characteristics of the effect. The turbulent model is utilized for characterization of flow over wing surface. Findings The numerical results show that the maximum change of the drag coefficient depends on the angle of attack, twist angle and ground clearance, in a decreasing order. Also, it is found that the lift coefficient increases as the ground clearance, twist angle and dihedral angle decrease. On the other hand, the sweep angle does not have a significant effect on the lift coefficient for the considered wing section and Reynolds number. Also, as the aerodynamic characteristics increase, the taper ratio befits in trailing state. Practical implications To design an aircraft, the effect of each design parameter needs to be estimated. For this purpose, the sensitivity analysis is used. In this paper, the influence of all parameter against each other including ground clearance, angle of attack, twist angle, dihedral angle and sweep angle for the NACA 6409 are investigated. Originality/value As a summary, the contribution of this paper is to predict the aerodynamic performance for the cruise condition. In this study, the sensitivity of the design parameter on aerodynamic performance can be estimated and the effect of geometrical characteristics has been investigated in detail. Also, the best lift to drag coefficient for the NACA 6409 wing section specifies and two types of taper ratios in ground effect are compared.

A comprehensive numerical study of battle damage and repairs upon the aerodynamic characteristics of an aerofoil

2010 ◽  
Vol 114 (1158) ◽  
pp. 469-484 ◽  
Author(s):  
M. Saeedi ◽  
F. Ajalli ◽  
M. Mani
Keyword(s):  
Flow Field ◽  
Numerical Solution ◽  
Mesh Generation ◽  
Unstructured Mesh ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
The Other ◽  
Stall Angle

Abstract A NACA 641-412 aerofoil with circle and star damage and also three repair configurations has been numerically investigated. Two different methods of mesh generation were employed: multi structured mesh for the star damaged aerofoil and unstructured mesh for the other aerofoils. The results show that the damage will cause a reduction in lift coefficient of the aerofoil and also a different stall angle relative to that of the undamaged aerofoil. Each kind of repair improves the aerodynamic characteristics of the aerofoil considerably. The flow Field inside the damage hole and the cavity caused by the repair sheets was also investigated. Finally, the numerical solution was qualitatively and quantitatively validated using the available experimental results.

Posterior approach for cervical intramedullary arteriovenous malformation with diffuse-type nidus

1999 ◽  
Vol 91 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Kenji Ohata ◽  
Toshihiro Takami ◽  
Alaa El-Naggar ◽  
Michiharu Morino ◽  
Akimasa Nishio ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Poor Prognosis ◽  
Posterior Approach ◽  
The Other ◽  
Anterior Spinal Artery ◽  
Neural Element ◽  
Feeding Artery ◽  
Diffuse Type ◽  
Content Type ◽  
Fine Print

✓ The treatment of spinal intramedullary arteriovenous malformations (AVMs) with a diffuse-type nidus that contains a neural element poses different challenges compared with a glomus-type nidus. The surgical elimination of such lesions involves the risk of spinal cord ischemia that results from coagulation of the feeding artery that, at the same time, supplies cord parenchyma. However, based on evaluation of the risks involved in performing embolization, together with the frequent occurrence of reperfusion, which necessitates frequent reembolization, the authors consider surgery to be a one-stage solution to a disease that otherwise has a very poor prognosis. Magnetic resonance (MR) imaging revealed diffuse-type intramedullary AVMs in the cervical spinal cords of three patients who subsequently underwent surgery via the posterior approach. The AVM was supplied by the anterior spinal artery in one case and by both the anterior and posterior spinal arteries in the other two cases. In all three cases, a posterior median myelotomy was performed up to the vicinity of the anterior median fissure that divided the spinal cord together with the nidus, and the feeding artery was coagulated and severed at its origin from the anterior spinal artery. In the two cases in which the posterior spinal artery fed the AVM, the feeding artery was coagulated on the dorsal surface of the spinal cord. Neurological outcome improved in one patient and deteriorated slightly to mildly in the other two patients. Postoperative angiography demonstrated complete disappearance of the AVM in all cases. Because of the extremely poor prognosis of patients with spinal intramedullary AVMs, this surgical technique for the treatment of diffuse-type AVMs provides acceptable operative outcome. Surgical intervention should be considered when managing a patient with a diffuse-type intramedullary AVM in the cervical spinal cord.

The Influence of Water Regime on the Performance of Aquatic Plants

1994 ◽  
Vol 29 (4) ◽  
pp. 127-132 ◽  
Author(s):  
Naomi Rea ◽  
George G. Ganf
Keyword(s):  
Deep Water ◽  
Aquatic Plants ◽  
Water Regime ◽  
Optimal Performance ◽  
Experimental Results ◽  
The Other ◽  
Full Potential ◽  
Influence Of Water ◽  
Emergent Species

Experimental results demonstrate bow small differences in depth and water regime have a significant affect on the accumulation and allocation of nutrients and biomass. Because the performance of aquatic plants depends on these factors, an understanding of their influence is essential to ensure that systems function at their full potential. The responses differed for two emergent species, indicating that within this morphological category, optimal performance will fall at different locations across a depth or water regime gradient. The performance of one species was unaffected by growth in mixture, whereas the other performed better in deep water and worse in shallow.

Islamic hedging for pilgrimage funds: case of Indonesia

2019 ◽  
Vol 11 (3) ◽  
pp. 328-341
Author(s):  
Rifki Ismal ◽  
Nurul Izzati Septiana
Keyword(s):  
Exchange Rate ◽  
The Other ◽  
Exchange Rate Risk ◽  
Content Type ◽  
Other Hand ◽  
Rate Risk ◽  
Risk Identify ◽  
Hajj Season ◽  
The Right ◽  
Very High

Purpose The demand for Saudi Arabian real (SAR) is very high in the pilgrimage (hajj) season while the authority, unfortunately, does not hedge the hajj funds. As such, the hajj funds are potentially exposed to exchange rate risk, which can impact the value of hajj funds and generate extra cost to the pilgrims. The purpose of this paper is to conduct simulations of Islamic hedging for pilgrimage funds to: mitigate and minimize exchange rate risk, identify and recommend the ideal time, amount and tenors of Islamic hedging for hajj funds, estimate cost saving by pursuing Islamic hedging and propose technical and general recommendations for the authority. Design/methodology/approach Forward transaction mechanism is adopted to compute Islamic forward between SAR and Rupiah (Indonesian currency) or IDR. Findings – based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Findings Based on simulations, the paper finds that: the longer the Islamic hedging tenors, the better is the result of Islamic hedging, the decreasing of IDR/USD is the right time to hedge the hajj funds and, on the other hand, the IDR/SAR appreciation is not the right time to hedge the hajj funds. Research limitations/implications The research suggests the authority to (and not to) hedge the hajj fund, depending on economic conditions and market indicators. Even though the assessment is for the Indonesian case, other countries maintaining hajj funds might also learn from this paper. Originality/value To the best of author’s knowledge, this is the first paper in Indonesia that attempts to simulate the optimal hedging of hajj funds.

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