Top PDF Flow Field Study Over the Wing of a Fighter-Type Aircraft Model

Flow Field Study Over the Wing of a Fighter-Type Aircraft Model

Flow Field Study Over the Wing of a Fighter-Type Aircraft Model

and e. At low angle of attack, α = 6°, the flow is characterized by completely attached flow with a weak tip vortex and a weak leading edge bubble, figure 4.d. The oil accumulation along the entire leading edge is an indication of the leading edge bubble, which is formed by the flow separation from the leading edge of the outer panel and reattaching on the surface again. However, for this angle of attack, α=6°, no separation is observed as shown by the straight attached lines. At 12° angle of attack, figure 4.e, the flow pattern is completely different. The wing tip vortex is still visible, but the attached flow region is less than that shown in figure 4.d. Instead there exists a large region of reversed flow and a large leading edge and wing tip separation regions shown by dots. This phenomenon causes a large decrease of lift along with a change in the pitching moment variation, deteriorating the aircraft stability and control criterion, hence its maneuverability. Shown in figure 4 is also the tuft flow visualization result of the present experiments. As can be seen, at low angle of attack, the tufts are moved toward the wing tip indicating the type of flow shown in figures 4.c and e. However, as the angle of attack increases, flow field study shows that the vortex covers a large portion of the wing and its shape is similar to that of delta wing vortices when they burst. The reason for the differences in the flow field seen between figures 4.a and e with those of figures 4.f-g is probably due to the differences in the shape of the wings, sweep angles, and the airfoil shape. However, the characters of the flow over all 3 wings are similar. As seen from these figures, figures 4.a-g, the flow structure over these types of wing, i.e. the wing of present experiment, is neither exactly the same as those of delta wing, vortex dominated flow, nor swept wing. The flow over cropped delta wings with sweep angles greater than 35deg prior to separation is of vortical type flow, not exactly vortex dominated flow. This means that the vortices formed over these wings have less energy, cover a large portion of the wing surface, and disappear at much lower angle of attack than those formed over delta wings with sweep angles greater than 65deg, figure 4a.
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Mean flow and turbulence measurements in the near field of a fighter aircraft wing-tip vortex at high Reynolds number and transonic flow conditions

Mean flow and turbulence measurements in the near field of a fighter aircraft wing-tip vortex at high Reynolds number and transonic flow conditions

The investigation of the wing-tip vortex generated by a model F/A-18 fitted with AIM-9 tip missiles, via five-hole probe measurements as well as hot-wire anemometry, has provided an overview of the mean and turbulent flowfield. At α = 4.5°, the tip vortex showed certain similarities with some of those described in the literature and generated at lower speeds with wings of simpler geometry. At α = 13°, the vortex increased in strength and size, the turbulence levels were an order of magnitude higher than at α = 4.5°, and the effects of the tip missile on the flow were more prominent. The missile body produced an axial velocity deficit which became more significant at the higher angle of attack, as well as increased turbulence levels due to its own wake and that of its canards and fins. The tip missile thus significantly increases the complexity of the studied flow. More detailed measurements, ideally at several streamwise stations, could help to understand more fully the development of this complex flowfield.
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Propulsion/airframe Integration Study of an Ultra High Bypass Ratio Turbofan and a Slotted, Natural-Laminar-Flow Wing

Propulsion/airframe Integration Study of an Ultra High Bypass Ratio Turbofan and a Slotted, Natural-Laminar-Flow Wing

CFD has allowed the investigation of unusual engine positions, especially over-the-wing concepts that may be used for future high-bypass ratio turbofans [43, 16]. More conventional engine locations have also been optimized. Stankowski et al. [68] assessed the influence of engine position, size, and power settings for a conventional, 300-seat aircraft at cruise with the engine located under the wing. It is estimated that for this type of aircraft, two turbofan engines account for 10-15% of the total aircraft drag. The propulsion integration study simulated the nine engine positions, and extrapolated all positions in between to approximate the optimum. Stankowski et al. [68] used a commercial CFD code, ANSYS Fluent. This study used the RANS equations and the k − ω shear stress transport (SST) turbulence model. The authors validated the clean aircraft model by comparing mesh and turbulence model dependence compared to the DPW6. Two powered- on engines were simulated. Engine 1 (E1) implemented current engine thrust requirements while Engine 2 (E2) had a larger fan diameter (D f an,E2 = 1.23D f an,E1 ) [68]. The smaller engine was
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Disaster Risk Reduction: A Case Study on Missing Aircrafts and Damage of Bridges due to Flood

Disaster Risk Reduction: A Case Study on Missing Aircrafts and Damage of Bridges due to Flood

The proposed idea deals with replacing aircraft detection using radar and GPS technology to Hyperspectral imaging (HSI). HSI deals with dividing images into spectral bands. This wide spectrum range offers high spectral resolution for easy detection and understanding. Spectral analysis of remotely sensed images provides more accurate information even for a small target. There are numerous applications for Hyperspectral imaging such as species detection in agriculture, rare minerals in geology, biomedical uses, military, etc. Detection of aircrafts from the spectral signature of Hyperspectral images can be useful in cases like missing of aircrafts, ships, etc.
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Unified Interconnect System for Next Generation Fighter Aircraft

Unified Interconnect System for Next Generation Fighter Aircraft

an enormous increase in capability, a further benefit is that FC- AE-1553 provides a bridge between legacy 1553 networks and the much higher-bandwidth FC networks. Therefore, an upgrade introducing an FC network to provide additional bandwidth in certain parts of an avionics architecture can be readily achieved while maintaining those parts that do not require a bandwidth increase intact. The FC-AE-ASM, RDMA and LP options are lightweight protocols that can be variously adopted for specific avionics applications, depending upon the exact requirement. FC-AE-ASM is a low-latency FC-4 layer communication protocol designed for avionic command, control, and signal processing usage. FC-AE-ASM protocol defines some necessary functions offered in FC-2 layer in order to provide corresponding ASM service in FC-4 layer. Every message in FC-AE-ASM comes from a single unidirectional exchange sequence. The protocol defines that a recipient may expect the message to arrive at a predetermined rate and does not know where the message is originating. If an ASM message exceeds the payload limit of a single FC frame, multiple frames will be used for transmission, and these frames will be reassembled based on Message ID field in ASM header. Moreover, FC-AE-ASM mainly uses Class 3 service which is a connectionless service without any notification of non- delivery. In this way, frames could be routed in different link to arrive at destination and decrease processing overhead brought by notification, which contributes to improve the utilization ratio in FC networks.
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Study of Optimal Design of Spar Beam for the Wing of an Aircraft

Study of Optimal Design of Spar Beam for the Wing of an Aircraft

For aerodynamic reasons, the wing cross section must have a streamlined shape commonly referred to as aerofoil sections. The aerodynamic forces on an aircraft change in magnitude, direction and location. Thus the required structure must be one that can efficiently resist loads causing combined tension, compression, bending and torsion. An aircraft wing is mainly subjected to lift, fuel, engine, landing gear, inertial, structural, nonstructural and other aerodynamic loads. In a cantilever wing, the wing bending moments decrease rapidly span wise from the maximum values at the fuselage support points. Spars are the main load carrying members in the wing running span wise direction. Wings of aircraft are attached at the root to the fuselage. Spars are stiffened enough to carry the loads and bending moments with minimum structural weight.
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Integrated Vehicle Health Management  System for Fighter Aircraft

Integrated Vehicle Health Management System for Fighter Aircraft

A fighter aircraft is more than a great looking flying machine equipped with lethal weapons & mind-blogging array of avionics & optoelectronics system. It is a fountainhead of cutting edge technologies, from the new composites to advanced designing, situation awareness & electronic warfare system, high end software, communication systems & optoelectronics systems. Buying an aircraft or it manufacturing under TOT or indigenous is nothing but dealing with a superb piece of machinery & keeping it running, so user should be able to control every aspect of the evolution of the aircraft & its systems. It is not just about a having a fighter aircraft equipped with advance avionics systems but also its maintenance. The primary goal of an aircraft is to complete its designated mission and most of the systems on board are allotted distributed functionalities towards achieving-the same. However down the line there exists the need for a system which monitors the status of the platform itself and thereby supplements roles like crew alerting or maintenance scheduling. This although does not figure in the primary roles but if the impact of this on the overall serviceability and mission capability of aircraft is accounted for, it presents astonishingly high criticality.
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Aerodynamic Analysis of Aircraft Wing

Aerodynamic Analysis of Aircraft Wing

An airfoil is defined as the state of a wing as seen in cross-area [3]. The basic design of the airfoil is shown in Fig.2. The first systematic study of airfoil shapes and their performances was constructed by the National Advisory Committee for Aeronautics, NACA, (the forerunner to NASA). The chord, camber and thickness are the most important features of airfoil geometry. The performance characteristics of cataloged airfoils typically given include the lift, drag, pressure distribution and moment about the aerodynamic center. Values for these characteristics have been measured by wind tunnel experimentation and are also determined through mathematical theory analyses, or using computational models with CFD simulation tools. In the previous report of our group [4], the wireless control system was designed to control and exchange data between aircraft model and base station. In this paper, CFD analysis on the aircraft wing model using NACA 2412 airfoil are performed by ANSYS software. The goal of this study is testing the fabricated wing model, which might be used for designing the future UAVs.
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HISTORY OF BRITISH AIR POWER DOCTRINE

HISTORY OF BRITISH AIR POWER DOCTRINE

Following the Second World War, air power theory and doctrine were highly influenced by the change which nuclear weapons brought to warfare and the concept of deterrence. The UK continued with a distinct programme to develop nuclear weapons and the development of the RAF V-Force consumed a great deal of resources and undoubtedly had a great influence on RAF doctrine. In addition, the RAF retained a deep global commitment in the retreat from Empire which required the active exploitation and application of air power all over the world. The scale and range of operations varied, but the level of commitments required the RAF to be proficient in every role and mission of air power. On the international front, the Royal Air Force was committed to NATO operations and the Service took a leading role in the development of NATO air doctrine.
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Multi-objective design of robust flight control systems

Multi-objective design of robust flight control systems

controller gains that minimize a weighted combination of the infinite–norm of the sensitivity function (for disturbance attenuation requirements) and complementary sensitivity function (for robust stability requirements). After considering a single operating point for a level flight trim condition of a F-16 fighter aircraft model, two different approaches will then be considered to extend the domain of validity of the control law: 1) the controller is designed for different operating points and gain scheduling is adopted; 2) a single control law is designed for all the considered operating points by multiobjective minimisation. The two approaches will be an- alyzed and compared in terms of efficacy and required human and computational resources.
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Partly Coupled Fluid Structure Interaction Analysis of an Aircraft Wing at Subsonic Speeds *BRUCE RALPHIN ROSE. J

Partly Coupled Fluid Structure Interaction Analysis of an Aircraft Wing at Subsonic Speeds *BRUCE RALPHIN ROSE. J

The term Computational Aeroelasticity (CAE) generally refers to the coupling of Computational Fluid Dynamics (CFD) with the structural dynamic tools to execute various aeroelastic analyses. [1], [5] Recently, CAE has gained an attention because of the progress in CFD, and in computer technologies. [7][9][13] The computational methods used to study the different aspects of aeroelastic response are not yet fully established, and many open issues remain to be resolved. For example, Variety of methods in CAE seeks out to create independent computational algorithm for the flow field and the structural subsystems. This method is burdened with the complications associated through the interactions between the two different simulation systems. [2][11][15] Few issues arise from the fact that CFD and CSD mesh systems are quite different. Frequently, the former uses an Eulerian or spatially fixed-coordinate system; the latter uses a Lagrangean or material fixed-coordinate system. [4][8][17][19] Hence, care must be taken to develop a suitable interfacing technique between the two modules. The primary concern while performing the coupled calculations is the different time scales linking the two modules. [6][21][25]
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Design and Analysis of Wing of an Ultralight Aircraft

Design and Analysis of Wing of an Ultralight Aircraft

L. Pascale & F. Nicolosi [6] in 2006, proposed a new design which is based on the idea to built a 4-seat aircraft with two light engines (Rotax 912S, usually used for ultralight aircraft) and to enter the market with a twin-engine aircraft with the same weight of a single engine aircraft. The present paper sho ws all main criteria on which the design of the aircraft and the choice of the configuration have been based. At Dipartimento di Ingegneria Aerospaziale (DIAS) of University of Napoli “Federico II” a deep aircraft aerodynamic investigation has been performed both numerically and experimentally through an extensive wind-tunnel test campaign. All tests and research activities have been focused on the analysis and optimization of aircraft aerodynamics. Detailed measurements of fuselage and nacelle aerodynamic effects. Design and tests of winglets to improve rate of climb in OEI (One Engine Inoperative) condition. Huiwen Hu and Huaien Kao [7] in 2009, presented the validation of finite element model (FEM) of an ultralight aircraft structure by using experimental modal analysis (EMA). The main structure of ultralight aircraft consists of the wings, the fuselage and the empennage structures, which are fabricated by means of aluminum tubes through the bolts, rivets and the brackets. A commercial code, ANSYS, is used to establish the FEM. Normal mode analysis is performed to obtain the natural frequencies and mode shapes under a completely free boundary condition. EMA is conducted on the wings, the fuselage and the integral structures to obtain their natural frequencies and mode shapes, respectively. The FEM is then validated and updated according to the correlation of natural frequencies and mode shapes between EMA and FEA. It is essential to assure that the FEM is equivalent to the real aircraft structure for the further structural analysis.
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Design and Analysis of Aircraft Wing

Design and Analysis of Aircraft Wing

In the present study, a general aviation airplane is designed and analyzed. The design process starts with a sketch of how the airplane is envisioned. Weight is estimated based on the sketch and a chosen design mission profile. A more refined method is conducted based on calculated performance parameters to achieve a more accurate weight estimate which is used to acquire the external geometry of the airplane. A three-dimensional layout of the airplane is created using RDS software based on conic lofting, then placed in a simulation environment in Matlab which proved the designs adherence to the design goals. In addition, static stress analysis is also performed for wing design purposes. Using the finite element software package COMSOL, the calculated aerodynamic loads are applied to the wing to check the wing reliability. It is shown that the designed wing could be a good candidate for similar general aviation airplane implementation.
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Total Technical Life Extension of Undercarriage of Fighter Aircraft by Rejuvenation

Total Technical Life Extension of Undercarriage of Fighter Aircraft by Rejuvenation

The recovery plan consisted of two main streams Technology and Supply Chain. The technology stream ensured quality of product and meeting the specific technological requirements and the supply chain stream was required to get the necessary spares and tools required to carry out the rejuvenation. Various processes were studied for this and before implementing these, the personnel were made to undergo rigorous training especially in the areas of Non-destructive testing. Personnel were also sent abroad to study similar processes carried out on similar components. Documents regarding some special tools and testers required were also procured and the supply chain team located similar indigenous tools for using during this process.
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Flow structure in a model of aircraft trailing vortices

Flow structure in a model of aircraft trailing vortices

increased dissipation are observed to develop on each vortex in the array. The lin- ear stability study found a local maximum in the growth-rate vs axial wave number curve (Figure 6.3) at around this wavelength; Viscosity most likely damps the higher growth rate, shorter wavelength modes in the viscous DNS. In Figure 7.1(a) it can be seen that globally, this growth of the initial perturbations leads to a slight increase in the volume averaged dissipation and a corresponding faster decay of kinetic en- ergy. As expected, the averaged circulation is unaffected by the axial velocity since its destabilizing effect acts on each vortex independently and does not lead to en- hanced inter-vortex vorticity convection. During this initial phase, the evolution of each vortex is qualitatively similar to that of an isolated vortex, and is best described in cylindrical components. Figure 7.3 shows that, similarly to the isolated case, the maximum axial velocity shows a sharp decrease initially while the azimuthal compo- nent maintains a constant gradual decay. Presumably, the mechanism is the same as for the Batchelor vortex studied by Jacquin and Pantano 25 , whereby the energy of the
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Numerical Modelling of Aircraft Wing Deflection Under Different Loading Conditions

Numerical Modelling of Aircraft Wing Deflection Under Different Loading Conditions

The use of finite element analysis in structural analysis have been increasing over the years as it has proven an alternative to mathematical analysis mostly giving a close approximation. The finite element technique of plane stress analysis has been presented in different papers. The technique has gained considerable recognition with application to problems associated with the aircraft industry. In all of these papers, however, the technique has been applied to problems associated with isotropic materials. Reference [3] examined the framework method and the stiffness element method closely and determined their applicability in handling problems in orthotropic plane stress. The concept of fracture mechanics and numerical approaches was introduced in [4] to solve interacting cracks problems in solid bodies which involves elastic crack interaction. A new computational fracture mechanics algorithm was developed by adopting stress singularity approach in finite element (FE) formulation. As a conclusion, the FE formulated approach was found to be at agreeable accuracy with analytical formulation.
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CFD Analysis of an Aircraft delta wing

CFD Analysis of an Aircraft delta wing

The standard technique in evaluating the lift and drag coefficients from an Euler CFD solution is to integrated the pressure on the surface [5]. As seen in Chapter 3, this method does not work for calculating the drag coefficients (all but one drag value was negative). This error occurs because the aircraft surface is represented by triangles; therefore high grid resolution must be used in order to accurately represent curved surfaces [6]. Also, errors are introduced from the subtraction of two large forces in the flow direction. Therefore, the pressure distribution must be accurately known in order to determine the drag force [7]. These two problems suggest that in order for a surface integration technique to be accurate, a fine computational grid must be used, resulting in long run times. Another problem with surface integration technique is that they combine different drag components into one resultant drag coefficient. It is important, especially in conceptual design, to know how the drag is being produced so the aircraft can be efficiently designed [7].These limitations of the surface integration technique have led researchers to look at other methods to evaluate the lift and drag coefficients generated by CFD. One method is the Wake Integration technique. In this method, the drag is computed from the physical phenomenon that causes drag forces [7]. This is done by evaluating the vortex and entropy produced on a plane perpendicular to the flow which lies downstream from the aircraft [6]. The vortices produced are results of the lift induced drag, and the entropy production is related to the wave drag [8]. Thus, this method will be used in this analysis since it is not as dependent on the grid resolution as surface integration, and it separates the drag components by the physical phenomena that create the drag.
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The Stability and Control of an Aircraft with an Adaptive Wing

The Stability and Control of an Aircraft with an Adaptive Wing

in Fig. 4.10 (b), for the aircraft was plotted versus time to demonstrate that the drag is reduced after the automated flap optimizes the wing. Figure 4.10 (c) shows the throttle reduction after the flap system is switched on. Much like the throttle, there is also a reduction in the fuel consumption indicating that the aircraft with the adaptive wing is indeed operating more efficiently at the same desired flight condition. From these plots it is clear that the auto-adaptive aircraft has drag benefits. The drag savings can be increased if the aircraft and airfoil are tailored for wing adaptation. Such a decrease in drag translates to a large benefit on the range, endurance, and V max of an aircraft. Future work in this area could provide
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Unmanned Aerial Vehicle For Surveillance

Unmanned Aerial Vehicle For Surveillance

Abstract: UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitoring, reconnaissance, data relay, and data collection or to enter the area which is not safe for human i.e. flood affected or virus affected area. Present paper discusses the systematic design, data analysis, different property calculations and then manufacturing of delta wing type of UAV with low cost which successfully flew in the sky in Mumbai. It measures the altitude, captures the real image as well as videos that used for the surveillance purpose.

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Design and Analysis of Boeing 747 Aircraft Wing Rib Using Composite Materials

Design and Analysis of Boeing 747 Aircraft Wing Rib Using Composite Materials

Study of behaviour of wings of aircraft is an important area of study in the science of aerodynamics. The beltings of the airflow around any moving object can – in principle – be found by resolving the Navier-Stokes equations of fluid dynamics. Except for simple geometries these equations are particularly solve difficult. But easier explanations can be described. To produce "lift" for a wing, it must be adjusted at a suitable angle of attack relative to the flow of air past the wing. When this takes place the wing deflects the downwards airflow,
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