bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling methane-air turbulent diffusion flame in a gas turbine combustor with artifical neural network
Authors: Mehdizadeh N. S. , Sinaei P. 
Published: February 2016

AbstractThe present paper reports a way of using an artificial neural network (ANN) for modelling methane-air jet diffusion turbulent flame characteristics, such as temperature and chemical species mass fractions in a gas turbine combustion chamber. Since the neural network needs sets of examples to adapt its synaptic weights in the training phase, we used pre-assumed probability density function (PDF) method and considered chemical equilibrium chemistry model to compute the flame characteristics for generating the examples of input-output data sets. In this approach, flow and mixing field results are presented with a non-linear first order k-ε model. The turbulence model is applied in combination with preassumed β-PDF modelling for turbulence-chemistry interaction. The training algorithm for the neural network is based on a back-propagation supervised learning procedure, and the feed-forward multilayer network is incorporated as neural network architecture. The ability of ANN model to represent a highly non-linear system, such as a turbulent non-premixed flame is illustrated, and it can be summarized that the results of modelling of the combustion characteristics using ANN model are satisfactory, and the CPU-time and memory savings encouraging.
Development of a proof–of–concept aircraft smart control system
Authors: Hutapea P. , Jacobs K. , Harper M. , Meyer E. , Roth B. 
Published: February 2016

AbstractHutapea et al showed that an actuation system based on shape memory alloy coils could be employed for a wing flap of an aircraft. A continued research and development of these previously demonstrated smart flight control mechanisms was performed with the goal to develop a proof-of-concept shape memory alloy (SMA) actuation system, which utilises SMA springs to control the six degrees of freedom of an aircraft. For this actuation system, the springs are heated via an electric current, causing the spring to contract as the metal’s phase changes from martensite to austenite. The contraction allows the springs to function as linear actuators for the aircraft’s control surfaces, specifically the flaps and ailerons on the wings and horizontal stabilisers and a rudder on the tail. As a significant advancement to the overall actuation system, an air burst-cooling system increases the cooling rate of the coils by means of forced convection. Computer-based finite element model analysis and experimental testing were used to define and optimise SMA spring specifications for each individual control surface design. A onesixth scale proof-of-concept model of a Piper PA-28 Cherokee 160 aircraft was constructed to demonstrate and to verify the final actuation system design.
Low noise engine design for the Silent Aircraft Initiative
Authors: Hall C. A. 
Published: February 2016

AbstractThe Silent Aircraft Initiative was a Cambridge-MIT Institute programme involving a large team of researchers from both the University of Cambridge and the Massachusetts Institute of Technology (MIT). The aim of the project was to produce a concept aircraft design that would be so quiet it would be imperceptible in the urban environments around airports.. This paper gives an overview of how all the sources of engine noise were carefully addressed within the Silent Aircraft design. Novel technologies, a new engine configuration, improved airframe integration, new operational procedures and advanced component design were all required in order to reduce the overall engine noise level to the Silent Aircraft target. The study suggests that in order to dramatically reduce the noise of future aircraft engines a number of major design changes must be combined.
The pilot model balked landing simulation project: A government, industry and national research cooperation
Authors: Hosman R. , Belyavin A. , Hörmann H. , Robel G. , Schuring J. , der Geest P. van , Towler J. 
Published: February 2016

AbstractThe introduction of new larger aeroplanes presents the ICAO Instrument Flight Procedures Panel (IFPP) with the need to review the requirements for the Obstacle Free Zone. To support future decisions, the IFPP took the initiative to ask for the development of pilot models which are capable to control the simulated aircraft during the approach — go-around manoeuvre. The aim of this development was to obtain a tool to perform Monte Carlo simulations for the determination of the flight path statistics of the manoeuvre. In 2001, both QinetiQ and the National Aerospace Laboratory (NLR) were invited to develop pilot models. The two pilot models are based on fundamentally different descriptions of a pilot’s control behaviour. The QinetiQ pilot model is based on a discrete-event representation of pilot control movements and has been developed in the Integrated Performance Modelling Environment (IPME). The NLR pilot model is based on control engineering and is a linear model with visual and motion feedback extended with stochastic disturbances. This development was supported by Boeing, which provided a simulation model of the B747–400 as the representative aircraft model. The integration of the pilot models with the aircraft model was performed by Boeing. Statistical data on the flight path tracking during the approach – go-around manoeuvre and on discrete pilot actions were obtained from simulations performed in a full flight simulator (FFS) at NASA Ames and a fixed-base simulator at Boeing. Both pilot models, the use of the statistical data from the simulations and the integration with the aircraft model are discussed in the paper.
Simulation of wake vortex effects for UAVs in close formation flight
Authors: Saban D. , Whidborne J. F. , Cooke A. K. 
Published: February 2016

AbstractThis paper addresses the development of multiple UAV deployment simulation models that include representative aerodynamic cross-coupling effects. Applications may include simulations of autonomous aerial refuelling and formation flying scenarios. A novel wake vortex model has been developed and successfully integrated within a Matlab/Simulink simulation environment. The wake vortex model is both sufficiently representative to support studies of aerodynamic interaction between multiple air vehicles, and straightforward enough to be used within real time or near real time air-to-air simulations. The model integration process is described, and computational results of a two-vehicle-formation flight are presented.
A multidisciplinary approach to structural health monitoring and damage prognosis of aerospace hotspots
Authors: Chattopadhyay A. , Peralta P. , Papandreou-Suppappola A. , Kovvali N. 
Published: February 2016

AbstractThe health monitoring and damage prognosis of aerospace hotspots is important for reducing maintenance costs and increasing in-service capacity of aging aircraft. One of the leading causes of structural failure in aerospace vehicles is fatigue damage. Based on the physical mechanism of damage nucleation and growth, a physics-based multiscale model is considered for fatigue damage assessment in metallic aircraft structures. A guided-wave based sensing approach is utilised to enable effective damage detection in a common structural hotspot: a lug joint. Finite element analysis is carried out with piezoelectric wafers bonded to the host structure and the simulated sensor signals are analysed. A damage classification strategy is developed, which integrates physically motivated time-frequency approaches with advanced stochastic modelling techniques. In particular, a variational Bayesian learning scheme is used to estimate the optimal model complexity automatically from the data, adapting the classifier for real-time use. Classification performance is studied as a function of signal-to-noise ratio and results are reported for the detection of fatigue crack damage in the lug joint. An adaptive hybrid prognosis model is proposed, which estimates the residual useful life of structural hotspots using damage condition information obtained in real-time.
New adaptive controller method for SMA hysteresis modelling of a morphing wing
Authors: Grigorie T. L. , Botez R. M. 
Published: February 2016

AbstractA neuro-fuzzy controller method for smart material actuator (SMA) hysteresis modelling is presented, conceived for a morphing wing application. The controller correlates each set of forces and electrical currents that are applied to the smart material actuators with the actuator elongation. The actuator is experimentally tested for four forces, using a variable electrical current. The final controller is obtained through the Matlab/Simulink integration of three independent neuro-fuzzy controllers, designed for the increase and decrease of electrical current, and for null electrical current in the cooling phase of the actuator. This final controller gives a very small error with respect to the experimental values.
Simulation of automatic helicopter deck landings using nature inspired flight control
Authors: Voskuijl M. , Padfield G. D. , Walker D. J. , Manimala B. J , Gubbels A. W. 
Published: February 2016

AbstractResearch studies have indicated that the optical flow parameter, time to close tau, is the basis of purposeful control in the animal world, and used by both fixed wing and helicopter pilots during manoeuvring. This parameter is defined as the instantaneous time to close a gap (spatial or force) at the current closing rate. A novel automatic flight control strategy has been developed that makes use of optical flow theory and in particular, the parameter tau. This strategy has been applied to two distinct problems; (1) the landing of a helicopter on a ship and (2) the lateral repositioning of a helicopter. The first is a challenging case because the landing of a helicopter on a ship is one of the most dangerous of all helicopter flight operations. Furthermore, helicopters are often subject to torque oscillations during rapid collective control, which increases pilot workload significantly when operating with low power margins and/or whilst performing tasks that require accurate heave control. The second case demonstrates the generality of the technique. Both automatic manoeuvres were simulated successfully within desired limits, with the novel control strategy creating a ‘natural’, smooth, tau motion.
Performing co-ordinated turns with articulated wing-tips as multi-axis control effectors
Authors: Bourdin P. , Gatto A. , Friswell M. I. 
Published: February 2016

AbstractThis paper investigates a novel method for the control of aircraft. The concept consists of articulated split wing-tips, independently actuated and mounted on a baseline flying wing. The general philosophy behind the concept was that adequate control of a flying wing about its three axes could be obtained through local modifications of the dihedral angle at the wing-tips, thus providing an alternative to conventional control effectors such as elevons and drag rudders. Preliminary computations with a vortex lattice model and subsequent wind tunnel tests and Navier-Stokes computations demonstrate the viability of the concept for co-ordinated turns, with individual and/or combined wing-tip deflections producing multi-axis, coupled control moments. The multi-axis nature of the generated moments tends to over-actuate the flight control system, leading to some redundancy, which could be exploited to optimise secondary objective functions such as drag or bending moment.
Helicopter icing
Authors: Cao Y. , Chen K. 
Published: February 2016

AbstractDue to constraints of natural condition, cost and of available time associated with model fabrication and for extensive wind-tunnel tests or flight tests, Computational Fluid Dynamics (CFD) simulation was considered an alternative means of providing air vehicle icing simulation and aeromechanic performance analysis. Full-scale icing experiments and, therefore, certification and cost can be significantly reduced by developing full-numerical simulation methods to evaluate the air vehicle performance for a wide range of icing conditions. This paper summarises helicopter icing simulation methods that include the development of helicopter aerodynamics, calculation methods of helicopter icing, icing protection system performance, icing effects on the helicopter performance, and some challenges in helicopter icing simulation.
An evaluation of the historical issues associated with achieving non-helicopter V/STOL capability and the search for the flying car
Authors: Saeed B. , Gratton G. B. 
Published: February 2016

AbstractCombined Vertical and short take-off and landing, or ‘V/STOL’ capability has been of great demand and interest in the field of aeronautics since the creation of the aircraft. V/STOL capability is a targeted capability for many projected or prototype future aircraft. Past V/STOL aircraft are reviewed and analysed with regard to their performance parameters. This research has found two embedded categories in this class of aircraft based on their propulsion systems, i.e. jet and non-jet propulsion, and highlights the significant performance differences between them. In light of historical experience the performance of a relatively new class of aircraft, the flying cars, has been evaluated.
On the aerodynamics of the Miles M.52 (E.24/43) – a historical perspective
Authors: Brinkworth B. J. 
Published: February 2016

AbstractThe aerodynamic design of the Miles M.52 experimental supersonic aircraft is reviewed relative to the state of knowledge at its time of 1943 – 1946. Drawing on widely-ranging material, much not previously published, this study enlarges upon, and in places amends, previous accounts of the project.Based on advice collated from the fields of aerodynamics and ballistics, Miles conceived an original and forward-looking design, backed by an extensive test programme. Novel solutions to new requirements in the areas of structures and systems provided a robust airframe, showing fair prospects of being stable and controllable throughout the specified flight envelope. An equally innovative power plant was devised for it by Whittle’s company, Power Jets Ltd.Contradictory predictions of its performance were made by Miles and the RAE, through differences in their estimations of fuselage drag. A new evaluation suggests that the available information would have shown the aircraft to be capable of providing vital aerodynamic data for the transonic and early supersonic regimes at a time when no other sources were available, though further engine development would be needed for it to reach its full potential.
Human-computer co-operative co-evolutionary method and its application to a satellite module layout design problem
Authors: Huo J-Z. , Teng H-F. , Sun W. , Chen J. 
Published: February 2016

AbstractThe layout design of a satellite module is a complex mechanical layout problem. Its main difficulties lie in combinatorial explosion of computational complexity, engineering complexity, and applicability in engineering practice. Inspired by the human-computer cooperation ideas, a human–computer co-operative co-evolutionary method for optimising layout design of a satellite module is developed. This method constructs the diversity reference set by using the diversity intelligence solutions (DIs) that are created by using the combinatorial operators of differential evolution (DE) and the blend crossover operator (BLX-a). During the co-evolution process of the presented method, the AIs, the DIs and the algorithm solutions are expressed by unified encoding strings and incorporated together to create new co-operative solutions. An instance of a satellite module layout design is presented to demonstrate the feasibility and effectiveness of the proposed method. Compared with the co-evolutionary approach and the all-at-once optimisation approaches, computational results show that the proposed method not only can produce better solutions, but also can better balance the conflicting objectives on the trade-off issues.
Numerical simulation of the flow field over conical, disc and flat spiked body at Mach 6
Authors: Mehta R. C. 
Published: February 2016

AbstractA forward facing spike attached to a hemispherical body significantly changes its flow field and influences aerodynamic drag and wall heat flux in a high speed flow. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag and heat load on the surface. Consequently, the geometry, that is, the length and shape of the spike, has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. It is, therefore, a potential candidate for aerodynamic drag reduction for a future high speed vehicle. Axisymmetric compressible laminar Navier-Stokes equations are solved using a finite volume discretisation in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the spike length and shape, and the spike nose configuration on the reduction of drag is numerically evaluated at Mach 6 at a zero angle-of-attack. The computed density contours agree well with the schlieren images. Additional modification to the tip of the spike to get different types of flow field such as the formation of a shock wave, separation area and reattachment point are examined. The spike geometries include the conical spike, the flat-disk spike and the hemispherical disk spike of different length to diameter ratios attached to the blunt body.
Fire and evacuation analysis in BWB aircraft configurations: computer simulations and large-scale evacuation experiment
Authors: Galea E. R. , Filippidis L. , Wang Z. , Ewer J. 
Published: February 2016

AbstractHow long would it take to evacuate a blended wing body (BWB) aircraft with around 1,000 passengers and crew? How long would it take an external post-crash fire to develop non-survivable conditions within the cabin of a BWB aircraft? Is it possible for all the passengers to safely evacuate from a BWB cabin subjected to a post-crash fire? These questions are explored in this paper through computer simulation. As part of project NACRE, the airEXODUS evacuation model was used to explore evacuation issues associated with BWB aircraft and to investigate fire issues, the CFD fire simulation software SMARTFIRE was used. The fire and evacuation simulations were then coupled to investigate how the evacuation would proceed under the conditions produced by a post-crash fire. In conjunction with this work, a large-scale evacuation experiment was conducted in February 2008 to verify evacuation model predictions. This paper presents some of the results produced from this analysis.
Radar target tracking in cluttered environment based on particle filtering
Authors: Huansheng N. , Weishi C. , Jing L. 
Published: February 2016

AbstractThis paper deals with the problem of radar target tracking in cluttered environment from plane position indicator (PPI) radar images collected by low-cost incoherent radar. For this purpose a new five-step technique is proposed, including background subtraction, clutter suppression, measurements extraction, tracking and data fusion; the tracking step uses a particle filtering based data association method. Radar measurements, including target information and clutter interference, are checked whether it belongs to tracking target by data association with Kalman predicted state. If the measurement is generated by target, target state is updated by Kalman filter, and vice versa the predicted state keeps invariant. Moreover, smoothed tracks are given by Kalman smoothing of filtering results. The performance of the tracking algorithm is deeply investigated against Monte Carlo simulations. Finally, the overall multi-frame-based technique is applied to two sets of live PPI radar images, and the results show the effectiveness of the proposed approach.
A finite element stress analysis of aircraft bolted joints loaded in tension
Authors: Oskouei R.H. , Keikhosravy M. , Soutis C. 
Published: February 2016

AbstractAccurate stress and strain analysis in bolted joints is of considerable interest in order to design more efficient and safer aerospace structural elements. In this paper, a finite element modelling of aluminium alloy 7075-T6 bolted plates, which are extensively used in aircraft structures, is discussed. The ANSYS Finite Element (FE) package was used for modelling the joint and estimating the stresses and strains created in the joint due to initial clamping forces and subsequent longitudinal tensile loadings. A double-lap bolted joint with a single bolt and nut was considered in the study. A three-dimensional (3D) finite element model of the joint was generated, and then subjected to three different simulated clamping forces followed by different levels of longitudinal tensile load. 3D surface-to-surface contact elements were employed to model the contact between the various components of the bolted joint. Friction effects were considered in the numerical analysis; and moreover, the clearance between the bolt and the plates was simulated in the model. FE results revealed beneficial compressive stresses near the hole edge as a result of applying the clamping. It was found that a higher clamping force can significantly decrease the magnitude of the resultant tensile stress at the hole edge and also bearing stress in the joint when subjected to the longitudinal tensile load.
A hybrid frequency-time domain technique for ground effect identification
Authors: Vitale A. , Genito N. , Garbarino L. , Ciniglio U. , Corraro F. 
Published: February 2016

AbstractThe estimation from flight data of aerodynamic parameters for vehicle in steady-state conditions, perturbed by an identification manoeuvre, is a well-established technology, whereas system identification from dynamic flight data is a subject of continuous interest. This paper presents a hybrid frequency and time domain technique for identification of vehicle longitudinal aerodynamic model, including the ground effect. Identification is performed in the framework of a multi-step approach, in which, first aerodynamic coefficients are estimated in the frequency domain, using an equation error method; then time domain techniques are applied to identify out of ground effect aerodynamic derivatives and ground effect model parameters. The technique was successfully applied to flight data of an experimental ultra light aircraft. Identification results showed that the proposed method works properly also in the dynamic phases of the flight or when no dedicated identification manoeuvres are executed. Moreover, the identified longitudinal aerodynamic model was used to design the flight control system that successfully performed many autonomous landings.