CFD analysis on the effect of winglet cant angle on aerodynamics of ONERA M6 wing

Winglets are one of important part of the wing that can reduce the vortex formed at the wing tips and therefore reduce induced drag by partial recovery of the tip vortex energy. Moreover, they increase the effective aspect ratio without actually increasing the wingspan. The geometry of the winglets plays an important role in their task. In the present research, computation of lift and drag of ONERA M6 wing have been conducted using ANSYS Fluent. The results have been validated with the NASA results. Flow features of the entire wing including winglet were examined at different cant angles of winglets of 30°, 60° and 75° at different angles of attack from 3° to 6°. It is observed that among the cases of this study, wings with winglets produces higher CL/CD ratio than the normal aircraft wing without winglets up to certain degree of angle of attack and by further increasing to higher angle of attack its performance getting diminished. The investigated concept of adaptable angle winglets appears to be a likely substitute for refining the aerodynamic effectiveness of an aircraft

Flow Anlaysis on Hal Tejas Aircraft using Computational Fluid Dynamics with Different Angle of Attack

In the current globalization, we can see many innovations being introduced or implemented in every aspect of field that are considered to be existed. Every country is aiming to develop its power over all the aspects that considered for comparison with other countries in order to stand at same level of competition with others. One such power considered by all countries to develop every possible way to have a healthy competition is the military power which involves basically innovations of fast moving aircraft having a high lift coefficient and low drag coefficient. Such an aircraft having the high lift and low drag coefficient is TEJAS (HAL) developed by country India on which the purpose of paper mainly sustains. The paper mainly focuses on steady-state flow analysis over aircraft TEJAS using the computer aided modelling techniques and also the comparison of the results obtained from the modelled techniques. The paper also outlines the designing of the structural model of the TEJAS in a modelling software, creation of a finite computational domain, segmentation of this domain into discrete intervals, applying boundary conditions such as velocity in order to obtain plots and desired results determining the coefficient of pressure, lift and drag coefficient, velocity magnitude etc. This paper also aims in creating awareness to the future students about the techniques involved and knowledge required for developing a designed modelled. This paper also highlights the use of CFD techniques involved for the purpose of fluid flow simulation of the aircraft especially performing the meshing techniques, pre and post processing techniques and finally the evaluation of the simulation. Finally this paper can be seen as source by future generation students in gaining knowledge about design, analysis and simulation of the structured model on various conditions, about the field of aerospace engineering and new innovations being developed and also about the career involved when the above fields were chosen foe specialization purpose

Experimental investigation of a new spiral wingtip

Experiments on the relative merits and demerits of slotted wingtips mimicking a bird’s primary feathers have been performed. The real emargination length of feather tips, their flexibility and curved shapes during cruise are considered in the present study. The experiments were performed at a Reynolds number of 3.7 x 105 on a symmetric flat plate half wing of aspect ratio 3. Lift, drag and pitching moments were measured using a six component aerodynamic balance. Four different shapes inspired by bird primary feathers have been analysed. The rigid curved tip performed the best increasing the L/D ratio by 20%. This improvement has been compared with forty different wingtips model available in the literature which shows that rigid curved tip provide better L/D performance. Based on this improvement the key performance indicator of Jet and propeller airplane has been calculated that shows a 7.8% and 9% increase in range for propeller and Jet airplane, respectively

The evaluation of lift and drag force for solid body with micro dimple

The present study explores the lift and drag mechanism, pressure distribution along the chord and flow visualization of the debossed dimpled- aerofoil with the aim to evaluation the effect of dimples on the aerodynamic characteristic on the aerofoil and find an optimisation on the dimples parameter in improving the aerodynamic performance. The issues on the fuel consumption, energy cost, aerodynamic performance efficiency for aerofoil application in turbine, automotive especially under unexpected weather condition such as air turbulence in air flight lead to the concern on improving the aerodynamic performance from time to time. In current context, the interaction of the dimple parameters influencing the aerodynamic behaviour of the aerofoil such as the dimple aspect ratio, shape, pitch resulting in variation of number of dimple is considered. An aerofoil sized 0.14m x 0.148m is tested under wind tunnel with different angle of attack and air velocity. The aerofoil flow visualizations under smoke test are captured with a high speed camera. A comparative study of the smooth and dimpled aerofoil with cylindrical (bluff) and hexagonal (blunt) dimple shape is investigated. From the result it is shown with the integration of dimple, the lift performance of the aerofoil is greatly improved with the delay of flow separation as a result from the streamwise vorticity reduces the turbulent skin drag. thus increasing the lift and the controllability of the aerofoil. The cylindrical dimpled aerofoil with the aspect ratio of 0.4 and pitch 8500 μm is highly recommended with the highest lift and lowest drag

Analisi computazionale preliminare di una winglet non-convenzionale

L'obiettivo di questo studio è sviluppare e valutare dal punto di vista prettamente aerodinamico, mediante metodi computazionali, una winglet a doppia estremità (up & down). Per lo sviluppo e l'ottimizzazione sono stati presi come riferimento i risultati ottenuti tramite il software xflr5 (metodo Vortex Lattice), mentre lo studio finale, nel confronto con la stessa ala senza winglet, è stato effettuato utilizzando SolidWorks Flow Simulation (analisi CFD). Ciò che si vuole dimostrare è che una winglet costruita in questo modo può, in linea generale, avere effetti benefici sulle prestazioni aerodinamiche. Questo tenendo conto, anzitutto, che un eventuale studio degli effetti generati sulla struttura alare diminuirebbe l'entità di questi benefici, ma, d'altra parte, le semplificazioni effettuate portano a pensare che esistano margini di miglioramento rispetto alla configurazione valutata

An Experimental and Theoretical Investigation of Novel Aircraft Drag Reduction

Air transportation is an important part of the world’s economic and indispensable transportation system. The major institutions in the world and the aviation authorities are well aware of the demanding expectations of the public for cheaper transportation cost and at the same time the need to reduce the negative impact of aircraft or air-transportation system on the atmosphere which include noise around airports and global warming to attain sustainability, reduction in the emission of green-house gases such Nitrogen oxides (x) and Carbon di-oxide. In order to achieve such a balance in the future, a strategy is required to match competitive excellence dedicated to meeting the demands of society while at the same time being cost effective for the airline companies and operating aviation authorities. Such a vision or concept cannot be realised without making further technological breakthroughs in engineering fields such as Aerodynamics and other discipline including materials and structures. Improving aircraft aerodynamic performance will have a direct impact on helping to implement these goals. Improving aircraft drag capabilities remains one of the big challenges faced by manufacturers of transport aircraft. It is known that for a typical transport aircraft drag, the induced drag amounts to about 40% of the total drag at cruise flight conditions and about 80 –90 percent of the total drag during aircraft take off. The skin friction drag constitute approximately one half of the total Aircraft drag at cruise flight configuration making up most of the remaining percentage of drag at cruise condition. The use of winglets or other wing-tip devices as a drag reduction device play a significant role in improving aircraft performance by acting as passive devices to reduce drag and enhance aircraft performance. In this thesis, four novel spiroid drag reduction devices are presented which were designed and optimised using STAR-CCM+ Optimate + which uses the SHERPA search algorithm as its optimisation tool. The objective of the optimisation process was set to maximise the lift-to-drag ratio. A low fidelity mesh model was used during the optimisation and the results were verified by using high-fidelity physics and mesh model. The developed devices showed an improve CL/CD ratio of up to 11 percent and improved CL by up to 7 percent while reducing CD by up to 4 percent with an 18 - 24 percent reduction in induced drag observed as well. The devices showed consistency in performance at several Mach numbers and angles of attacks. Thus, suggesting that such devices could be used over a wide range of flight regimes on aircraft or UAVs. The study also successfully demonstrated the capability to using this optimisation process in the design and development of such devices. Furthermore, a numerical investigation and wind tunnel verification study was performed on a wing tip turbine to ascertain the aerodynamic performance modification of using such a device at several Mach numbers, angles of attack, propeller rpms and sensitivity of propeller nacelle positions at the wing tip. The obtained results revealed a trend on the nacelle position to achieve the most improved aerodynamic performance. A CL/CD ratio improvement of up to 7 percent, CL modification of approximate 4 percent and CD reduction of up to 4 percent were achieved. In addition to demonstrate an appreciation of some of the wider implication of installing wing tip devices, a flutter analysis on a rectangular clean wing with added variable mass at the wing tip was performed. The result showed that the added masses had no significant implication on the flutter characteristics of the wing