bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods for the design of energy efficient high speed aerospace vehicles
Authors: Riggins D. , Taylor T. , Terhune L. , Moorhouse D.
Published: February 2016

This paper continues development of the fundamental analytical science, methodology and tools required for the analysis, design, and optimisation of high speed aerospace vehicles in terms of the efficient use of on-board energy. Specifically, it presents the complete second-law characterisation and related system-level energy management effectiveness for high-speed vehicles (coupling both aerodynamic and propulsive subsystems). Modelling of the fluid dynamics utilises high-level (multi-dimensional) flow-fields representative of generic configurations of interest. Capability has been recently developed which allows detailed second-law performance audits in terms of the ‘common currency’ of entropy generation for high-speed vehicles (involving complete synthesis of both internal and external flow-fields, i.e. both aerodynamic and propulsive sub-systems). This capability is now extended to encompass and utilise multi-dimensional flow-fields generated by computational fluid dynamics solvers, including Navier-Stokes solvers. Furthermore, the methodology is shown in this paper to provide insight and fundamental direction for management of onboard energy (‘price paid’) for maximum performance missions.
A proposed reference framework for unmanned aerial vehicle and system airworthiness requirements
Authors: Maneschijn A. , Jones T. , Backström T. W. von , Ingham L. A.
Published: February 2016

Various programmes are underway internationally to establish legislative instruments for regulating civil and military unmanned aerial vehicles and systems. An analysis of a selection of these programmes revealed that the approaches used for airworthiness regulation are not harmonised and are usually limited to specific unmanned aerial vehicle types, indicating the need for a generic framework for airworthiness requirements. A functional Reference Framework for unmanned aerial vehicle and system airworthiness requirements was developed using Annex 8 of the Chicago Convention as a reference basis, supplemented with airworthiness procedures and functional requirements derived from manned aircraft regulations, unmanned aerial vehicle and system airworthiness material, and flightworthiness guidelines for reusable launch vehicles. Various airworthiness elements were identified for which further research is required to develop appropriate airworthiness requirements. This paper summarises the development of the framework and proposes the Reference Framework as a functional basis for generating comprehensive South African civil and military airworthiness requirements for unmanned aerial vehicles and systems.
High resolution computational unsteady aerodynamic techniques applied to manoeuvring UCAVs
Authors: Morton S. A. , Cummings R. M. , Forsythe J. R. , Wurtzler K.
Published: February 2016

A method of high resolution simulation is proposed for Unmanned Combat Air Vehicles (UCAVs) undergoing manoeuvress at high angle-of-attack or transonic speeds. Motivation for the need to develop such a method is first presented to show payoff in the design cycle, followed by results of using the method on current manned fighter aircraft. Finally, a notional UCAV shape from Boeing military aircraft is presented to show the possibilities of how the method can accurately capture the relevant phenomenon of these difficult flight regimes.
A review of some current research on pressure sensitive paint and thermographic phosphor techniques
Authors: Kontis K.
Published: February 2016

The paper discusses the development and application activities within the Aero-Physics and Measurement Technology Laboratory at the University of Manchester on pressure sensitive paint and thermographic phosphor optical imaging systems for gas dynamic applications. It provides a brief review of the basic principles, fundamental theory, properties, chemical characteristics and bonding technologies associated with the two systems. A number of case studies are presented, which exhibit the range of applicability, limitations and potential for further development of the technologies.
Modelling a helicopter rotor’s response to
wake encounters
Authors: Whitehouse G. R. , Brown R. E.
Published: February 2016

In recent years, various strategies for the concurrent
operation of fixed-and rotary-wing aircraft have
been proposed as a means of increasing airport
capacity. Some of these strategies will increase the
likelihood of encounters with the wakes of aircraft
operating nearby. Several studies now exist where
numerical simulations have been used to assess the
impact of encounters with the wakes of large
transport aircraft on the safety of helicopter
operations under such conditions. This paper
contrasts the predictions of several commonly-used
numerical simulation techniques when each is used to
model the dynamics of a helicopter rotor during the
same idealised wake encounter. In most previous
studies the mutually-induced distortion of the wakes
of the rotor and the interacting aircraft has been
neglected, yielding the so-called ‘frozen vortex’
assumption. This assumption is shown to be valid
only when the helicopter encounters the aircraft
wake at high forward speed. At the low forward
speeds most relevant to near-airfield operations,
however, injudicious use of the frozen vortex
assumption may lead to significant errors in
predicting the severity of a helicopter’s response
to a wake encounter.
Studies on high speed jets from nozzles with internal grooves
Authors: Elangovan S. , Rathakrishnan E.
Published: February 2016

Experiments were carried out on jets issuing from circular nozzles with grooved exits and the results compared with those of the plain nozzle. The plain nozzle had an exit diameter of 10mm. Because of the introduction of semi-circular grooves at the exit, the effective or equivalent diameter of the grooved nozzles was 10·44mm. The groove lengths were varied as 3, 5 and 8mm. The nozzles were operated at fully expanded sonic and underexpanded exit conditions. The corresponding fully expanded Mach numbers were 1·0 and 1·41. The shock cell structure of the underexpanded jets from grooved nozzles appeared to be weaker than that of the plain nozzle, as indicated by lesser amplitudes of the cyclic variation of the Pitot pressure. The iso-Mach contours indicate that the jet spread along the grooved plane is significantly higher than that along the ungrooved plane. Off-centre peaks were observed in the mean pressure profile of underexpanded jets from grooved nozzles. They were probably due to the streamwise vortices shed from the grooves.
Active control of swept shock wave/turbulent boundary-layer interactions
Authors: Couldrick J. S. , Gai S. L. , Milthorpe J. F. , Shankar K.
Published: February 2016

This paper looks at active control of the swept shock wave/turbulent boundary-layer interaction using smart flap actuators. The actuators are manufactured by bonding piezoelectric material to an inert substrate to control the bleed/suction rate through a plenum chamber. The cavity provides communication of signals across the shock, allowing rapid thickening of the boundary-layer approaching the shock, which splits into a series of weaker shocks forming a lambda shock foot, reducing wave drag. Active control allows optimum control of the interaction, as it would be capable of positioning the control region around the original shock position and control the rate of mass transfer.
Unsteady aerodynamic model of a cargo container for slung-load simulation
Authors: Cicolani L. S. , da Silva J. G. A. , Duque E. P. N. , Tischler M. B.
Published: February 2016

The problem of simulation models capable of predicting the aerodynamic instability of helicopter slung-load cargo containers and bluff bodies is addressed. Instability for these loads is known to depend on unsteady frequency-dependent aerodynamics, but simulation models that include the unsteady aerodynamics do not currently exist. This paper presents a method for generating such models using computational fluid dynamics (CFD) to generate forced-oscillation aerodynamic data and frequency domain system identification techniques to generate a frequency response from the CFD data and to identify a transfer function fit to the frequency response. The method is independent of the responsible flow phenomenon and is expected to apply to bluff-bodies generally. Preliminary results are presented for the case of the 6- by 6- by 8-ft CONEX (container express) cargo container. The present work is based on two-dimensional (2D) aerodynamic data for the CONEX side force and yaw moment generated by a forced oscillation in which frequency is varied smoothly over the range of interest. A first-order rational polynomial transfer function is found adequate to fit the aerodynamics, and this is shown to provide a good match with flight test data for the yawing motion of the CONEX.
Analysis of compressible potential flow over aerofoils using the dual reciprocity method
Authors: Cavalieri A. V. G. , Soviero P. A. O.
Published: February 2016

The use of the linearised potential model for the analysis of compressible flows is quite widespread, and provides good results for subsonic and supersonic flows. However, the calculation of aerofoils and wings subject to transonic flows requires a non-linear model, such as the transonic small-disturbance (TSD) potential equation. The solution of the problem by a singularity distribution requires singularities over the field, as well as panels on the boundary, characterising the procedure known as field panel method. The present work shows results of calculations of the transonic small-disturbance potential equation for flows without shock waves using the dual reciprocity method (DRM), which permits calculation of integrals only at the boundary of the problem, without the need of field distributions. This approach, compared to the field panel methods, takes considerably less computer time, and shows a significant improvement when compared to results of linear theory without much additional computer time, making this technique adequate to design phases of aircraft. Pressure distribution results show good agreement with other methods found in litterature. The low computational cost of the present method allows us to perform parametric tests and explore the effects of thickness and Mach number on the lift and pitching moment coefficients. A discussion of the physical effect of these parameters on the problem is presented, and the thickness of the aerofoil is shown to increase the lift and change the position of the aerodynamic centre. However, this non-linear effect depends on the precise shape of the thickness distribution.
Helicopter brownout – Can it be modelled?
Authors: Phillips C. , Kim H. W. , Brown R. E.
Published: February 2016

Significant progress has been made to date in modelling, computationally, the formation and development of the dust cloud that forms in the air surrounding the rotorcraft under brownout conditions. Modern computational methods are able to replicate not only the development of the dust cloud in appropriate operational scenarios, but also the sensitivity of the shape and density of the dust cloud to the detailed design of the rotorcraft. Results so far suggest that attempts to ameliorate brownout by aerodynamic means, for instance by modifying the rotor properties, will be frustrated to some extent by the inherent instability of the flow field that is produced by the helicopter. Nonetheless, very recent advances in understanding the fundamental mechanisms that lead to the formation of the dust cloud may allow substantial progress to be made once certain elements of the basic physics of the problem are more fully understood and better quantified.
The space debris environment: future evolution
Authors: Lewis H. G. , Swinerd G. G. , Newland R. J.
Published: February 2016

Space debris represents a significant risk to satellite operations, due to the possibility of damaging or catastrophic collisions. Consequently, many satellite operators screen the orbiting population for close approaches with their on-orbit assets and a public conjunction assessment service, Satellite Orbital Conjunction Reports Assessing Threatening Encounters in Space (SOCRATES), generates close approach predictions on a daily basis for all satellite payloads in the catalogue. These screening capabilities are used to inform operational decisions relating to risk mitigation but it is anticipated that the demands placed on these services will increase as debris becomes more prolific. This hypothesis is explored in a preliminary analysis of conjunction data for the years 2004 to 2009 and a new ‘Business as usual’ study using the Debris Analysis and Monitoring Architecture for the Geosynchronous Environment (DAMAGE) model. The results suggest a 50% increase in the number of close approaches reported by SOCRATES (or its equivalent) within the next ten years. By 2059, daily conjunction reports could contain over 50,000 close approaches below 5km, affecting the demands placed on tracking facilities and satellite resources.
The influence of Reynolds and Mach numbers on two-dimensional wind-tunnel testing: An experience
Authors: Rasuo B.
Published: February 2016

In this note, the experimental results of wind-tunnel measurements of lift coefficient and lift-curve slope for aerofoil NACA 0012 obtained from the VTI-Institute Zarkovo, are presented. The results were obtained from tests and integrations of surface static-pressure data over a model of the NACA 0012 aerofoil section. The data were obtained for a free-stream Mach number range of 0·25-0·8 and a chord Reynolds number range of 2-25MRe. The essential results of these measurements along with the results from other authors are presented and evaluated. The principal factors which influence the accuracy of two-dimensional wind-tunnel test results are analysed. The influences of Reynolds number, Mach number and wall interference with reference to solid and flow blockage as well as the influence of side-wall boundary-layer control are analysed. Interesting results brought to light the Reynolds number effects of the test model versus Reynolds number effects of the facility in subsonic and transonic flow as well as the effects of the side-wall boundary-layer control and wall interference.
Aircraft conceptual design for optimal environmental performance
Authors: Henderson R. P. , Martins J. R. R. A. , Perez R. E.
Published: February 2016

Consideration of the environmental impact of aircraft has become critical in commercial aviation. The continued growth of air traffic has caused increasing demands to reduce aircraft emissions, imposing new constraints on the design and development of future airplane concepts. In this paper, an aircraft design optimisation framework is used to design aircraft that minimise specific environmental metrics. Multidisciplinary design optimisation is used to optimise aircraft by simultaneously considering airframe, engine and mission. The environmental metrics considered in this investigation are CO2emissions — which are proportional to fuel burn — and landing-takeoff NOxemissions. The results are compared to those of an aircraft with minimum direct operating cost. The design variables considered in the optimisation problems include aircraft geometry, engine parameters, and cruise settings. An augmented Lagrangian particle swarm optimiser and a genetic algorithm are used to solve the single objective and multi-objective optimisation problems, respectively.
Aerodynamics modelling for training on the edge of the flight envelope
Authors: Gingras D. R. , Ralston J. N.
Published: February 2016

Aircraft upset and Loss of Control (LOC) is a leading cause of accidents in commercial and general aviation aircraft operations. A number of measures have been taken in the commercial segment to improve training and awareness of this problem and several organisations offer in-flight training to enhance awareness. In relative terms, in both commercial and general aviation sectors, the use of Full Flight Simulators (FFS) and Flight Training Devices (FTD) for this purpose is minimal. A key reason for this is the limited capability and coverage of flight models used in these devices. This paper provides examples of the limitations in civilian simulators in contrast to military efforts that have been using full envelope modelling for decades to enhance pilot training. The paper also presents techniques used in full-envelope modelling, their validity, and a regulatory vehicle that is in-line with current international guidelines for application to civilian trainer development.
A hybrid fuzzy logic proportional-integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy Part 1: Morphing system mechanisms and controller architecture design
Authors: Grigorie T. L. , Botez R. M. , Popov A. V. , Mamou M. , Mébarki Y.
Published: February 2016

The present paper describes the design of a hybrid actuation control concept, a fuzzy logic proportional-integral-derivative plus a conventional on-off controller, for a new morphing mechanism using smart materials as actuators, which were made from shape memory alloys (SMA). The research work described here was developed for the open loop phase of a morphing wing system, whose primary goal was to reduce the wing drag by delaying the transition (from laminar to fully turbulent flows) position toward the wing trailing edge. The designed controller drives the actuation system equipped with SMA actuators to modify the flexible upper wing skin surface. The designed controller was also included, as an internal loop, in the closed loop architecture of the morphing wing system, based on the pressure information received from the flexible skin mounted pressure sensors and on the estimation of the transition location.

The controller’s purposes were established following a comprehensive presentation of the morphing wing system architecture and requirements. The strong nonlinearities of the SMA actuators’ characteristics and the system requirements led to the choice of a hybrid controller architecture as a combination of a bi-positional on-off controller and a fuzzy logic controller (FLC). In the chosen architecture, the controller would behave as a switch between the SMA cooling and heating phases, situations where the output current is 0A or is controlled by the FLC.

In the design phase, a proportional-integral-derivative scheme was chosen for the FLC. The input-output mapping of the fuzzy model was designed, taking account of the system’s error and its change in error, and a final architecture for the hybrid controller was obtained. The shapes chosen for the inputs’ membership functions were s -function, π-function, and z -function, and product fuzzy inference and the center average defuzzifier were applied (Sugeno).
Aerodynamics of an aerofoil in transonic ground effect: Methods for blowdown windtunnel scale testing
Authors: Doig G. , Barber T. J. , Neely A. J. , Myre D. D.
Published: February 2016

Experimental aerodynamic testing of objects in close ground proximity at high subsonic Mach numbers is difficult due to the construction of a transonic moving ground being largely unfeasible. Two simple, passive methods have been evaluated for their suitability for such testing in a small blowdown wind tunnel: an elevated ground plane, and a symmetry (or mirror-image) approach. The methods were examined using an unswept wing of RAE2822 section, with experiments and Reynolds-Averaged Navier Stokes CFD used synergistically to determine the relative merits of the techniques. The symmetry method was found to be a superior approximation of a moving ground in all cases, with mild discrepancies observed only at the lowest ground clearance. The elevated ground plane was generally found to influence the oncoming flow and distort the flowfield between the wing and ground, such that the method provided a less-satisfactory match to moving ground simulations compared to the symmetry technique.
Hovering rotor computations using an
aeroelastic blade model
Authors: Dehaeze F. , Barakos G. N.
Published: February 2016

In this paper, helicopter rotor blades are analysed in
hover using computational fluid dynamics (CFD)
coupled with a structural model. The method relies
on a mesh deformation algorithm that allows for
exchange of forces and deformations between a
beam-based finite-element model and the fluid flow
volume mesh. The method is demonstrated against
experimental data, and the aerodynamic predictions
appear to improve when the aeroelastic model is
used. For all employed cases the flexibility of the
method allows the CFD mesh deformation to be spread
over the computational domain in a controlled
fashion. The influence of the aeroelastic
deformations on the blade loads was limited yet
evident on the rotor performance. The lack of
adequate test cases and experiments for validation
of CFD/CSD methods is also highlighted.
Effect of thickness and angle-of-attack on the aeroelastic stability of supersonic fins
Authors: Firouz-Abadi R. D. , Alavi S. M.
Published: February 2016

This paper aims at developing an aeroelastic model for the instability analysis of supersonic thick fins. To this aim the modal analysis technique is used for the structural dynamics modelling of a fin with a general structure. An unsteady aerodynamic model is applied based on the shock/expansion analysis over the flat surfaces of the fin along with local application of the piston theory. Assuming a supersonic fin with an arbitrary polygonal cross-section, thickness and initial angle-of-attack, the steady flow properties (e.g. Mach number, density and temperature) are calculated over the flat surfaces of the fin. Then, assuming small amplitude vibrations, the generalised aerodynamic forces are obtained in terms of the structural modal coordinates. Using the obtained model, the effect of thickness, initial angle-of-attack, taper ratio and sweep angle on the aerodynamic derivatives and aeroelastic stability of the fin are studied which show their remarkable effects on the instability Mach number and its type. Specially, the presented results show that increasing the fin thickness dramatically diminishes the stability margin mainly at low angles of attack. Also a sharp decrease of the divergence Mach number is observed by increasing the fin’s incidence angle.
Operational performance of inlet barrier filters for rotorcraft
Authors: Bojdo N. , Filippone A.
Published: February 2016

This contribution addresses the subject of engine inlet barrier filters (IBF) for rotorcraft. The purpose of an IBF is to mitigate the risk of particle ingestion by the engine, a situation that can cause irrevocable damage to key components. The risk is significantly elevated during a brownout landing, in which the rotor wake of a descending helicopter interacts with loose ground sediment, causing the generation of a dust cloud. In such a condition, an IBF successfully removes particles from the engine-bound air at the expense of a pressure drop, which grows temporally. The increase in pressure drop is caused by but not limited to an increase in incident velocity and a decrease of mean particle size; however the rate may be slowed by operating the filter at a tangential angle to the flow. The current work presents findings of a parametric study into the factors affecting particle accumulation and the consequential loss of inlet total pressure.
Shape optimisation using CAD linked free-form deformation
Authors: Nurdin A. , Bressloff N. W. , Keane A. J. , Holden C. M. E.
Published: February 2016

Free-form deformation (FFD) is a method first introduced within the graphics industry to enable flexible deformation of geometric models. FFD uses an R3 to R3 mapping of a deformable space to the global Cartesian space to produce the geometry deformation. This method has been extensively used within the design optimisation field as a shape parameterisation technique. Typically it has been used to parameterise analysis meshes, where new design geometries are produced by deforming the original mesh. This method allows a concise set of design variables to be used while maintaining a flexible shape representation. However, if a computer aided design (CAD) model of the resulting geometry is required, reverse engineering techniques would need to be utilised to recreate the model from the deformed mesh. This paper extends the use of FFD within an optimisation routine by using FFD to directly parameterise a CAD geometry. Two methods of linking the FFD methods with the CATIA V5 CAD package are presented. Each CAD integration technique is then critiqued with respect to shape optimisation. Finally the set-up and initialisation of a case study is illustrated. The case study chosen is the aerodynamic optimisation of the wing-fuselage junction of a typical passenger aircraft.
Helicopter flight characteristics in icing conditions
Authors: Cao Yihua , Li Guozhi , Hess R. A.
Published: February 2016

A method to predict the effects of rotor icing on the flight characteristics of a UH-60A helicopter is presented. By considering both natural ice shedding and different types of ice accretion due to local temperature variations on the blade surface, an improved rotor icing model was developed. Next, the effects of icing on rotor force, torque and flapping were incorporated in a nonlinear helicopter dynamic model. Based upon icing design envelopes in cumuliform clouds, trim and stability characteristics were studied. Further development of the helicopter state-space model allowed control and handling qualities characteristics to be investigated with variation of the three icing-related cloud variables (atmospheric temperature, liquid water content, and median volumetric diameter). Results indicated that this method of evaluating rotorcraft icing is both feasible and useful.
Multi-disciplinary simulation of propeller-turboprop aircraft flight
Authors: Filippone A. , Mohamed-Kassim Z.
Published: February 2016

This contribution presents a novel simulation for a fixed-wing aircraft powered by gas turbine engines and advanced propellers (turboprops). The work is part of a large framework for the simulation of aircraft flight through a multi-disciplinary approach. Novel numerical methods are presented for flight mechanics, turboprop engine simulation (in direct and inverse mode), and propeller dynamics. We present in detail the integration of the propeller with the airframe, aircraft and tonal noise model. At the basic level, we address a shortfall in multi-disciplinary integration in turboprop-powered aircraft, including economical operations and environmental emissions (exhausts and noise). The models introduced are based on first principles, supplied with semi-empirical correlations, if required. Validation strategies are presented for component-level analysis and system integration. Results are presented for aerodynamics, specific air range, optimal cruise conditions, payload-range performance, and propeller noise. Selected results are shown for the ATR 72-500, powered by PW127M turboprop engines and F568-1 propellers.
Characterising low-speed, transitional cavity flow
Authors: Ng Y. T.
Published: February 2016

In various studies involving subsonic transition cavity flows, terms like ‘transitional-open’ and ‘transitional-closed’ cavity flow regimes are used in the literature. However, the exact fluid dynamic criteria to distinguish them have not been firmly established. The present work attempts to clarify this. Experiments to measure static pressure and fluctuating pressure distribution in a rectangular cavity with length-to-depth (L/D) ratio of 3 to 20 were performed. Based on pressure measurements on the front, bottom and rear faces of the cavity, additional criteria are established to clearly distinguish the range of critical L/D (or (L/D)cri) where these different transitional cavity flow regimes occur. The present work ascertains that the (L/D)cri for open and transitional-open cavity flow is 6·0-6·5, for transitional-open and transitional-closed cavity flow is 9-10 and for transitional-closed and closed cavity flow is 14-15. Flow visualisation qualitatively supports the flow pattern in the different cavity flow regimes.
Towards understanding effects of non-linear flight control system elements on inexperienced pilots
Authors: Lone M. M. , Ruseno N. , Cooke A. K.
Published: February 2016

This note presents the experimental method and results from a series of desktop simulation tests designed to investigate the manual control characteristics of relatively inexperienced civil pilots; with an average age and experience of 24 years and 66 hours respectively. Increased encroachment into non-linear command gearing was found to make aggressive subjects resort to high levels of crossover regression. The combined effects of rate-limiting and non-linear command gearing were observed only for demanding tasks during which over-control was a typical feature.
A finite element analysis of impact damage in composite laminates
Authors: Shi Y. , Soutis C.
Published: February 2016

In this work, stress-based and fracture mechanics criteria were developed to predict initiation and evolution, respectively, of intra- and inter-laminar cracking developed in composite laminates subjected to low velocity impact. The Soutis shear stress-strain semi-empirical model was used to describe the nonlinear shear behaviour of the composite. The damage model was implemented in the finite element (FE) code (Abaqus/Explicit) by a user-defined material subroutine (VUMAT). Delamination (or inter-laminar cracking) was modelled using interface cohesive elements and the splitting and transverse matrix cracks that appeared within individual plies were also simulated by inserting cohesive elements between neighbouring elements parallel to the fibre direction in each single layer. A good agreement was obtained when compared the numerically predicted results to experimentally obtained curves of impact force and absorbed energy versus time. A non-destructive technique (NDT), penetrant enhanced X-ray radiography, was used to observe the various damage mechanisms induced by impact. It has been shown that the proposed damage model can successfully capture the internal damage pattern and the extent to which it was developed in these carbon fibre/epoxy composite laminates.
Predicting low-velocity impact damage in composites by a quasi-static load model with cohesive interface elements
Authors: Zhang X. , Bianchi F. , Liu H.
Published: February 2016

A numerical model is developed for predicting low-velocity impact damage in laminated composites. Stacked shell elements are employed to model laminate plies with discrete interface elements in pre-determined zones to model the onset and propagation of matrix cracks and delamination. These interface elements are governed by a bi-linear cohesive failure law. Cohesive element zone size is determined by a separate finite element analysis using solid elements to identify the stress concentration sites. In order to save the computational effort, low-velocity impact load is modelled by quasi-static loading. Influence of contact force induced friction on shear driven mode II delamination is modelled by a friction model. For a clustered cross-ply laminate, calculated impact force and damage area are in good agreement with the test results. It is shown that matrix cracks should be included in the model in order to simulate delamination in adjacent interface. The practical outcome of this research is a validated modelling approach that can be further improved for predicting low-velocity impact damage in other stacking sequences.
Effect of autopilot modes on flight performances of electric mini-UAVs
Authors: Guglieri G.
Published: February 2016

Great attention is focused on the development of both remotely controlled and unmanned flying vehicles. As a matter of fact, the design of such vehicles is a topical direction of development for modern aeronautics. Among such promising flying vehicles, micro- and mini-UAVs play a leading role. The present paper proposes a method to validate the inclusion of the relevant modelling elements in a comprehensive simulation tool reproducing some of the flight phases of a mini-UAV. The energy balance budget and the dynamic response of the aircraft during the automatic flight are investigated, assessing the impact of autopilot configuration, such as altitude-airspeed holding modes and suggesting a setting guideline for flight mode selection compatible with the features of commercial autopilots.
Design and optimisation of the external load bearing carry through structure of a columned multi bubble fuselage
Authors: Cho S. H. , Bil C. , Adams R.
Published: February 2016

The blended wing-body configuration holds a major structural design challenge at the centre-body where the structure must support both wing bending loads and internal cabin pressure. A membrane approach is proposed which decouples the loads to allow their resistance by two independent structures: an inner membrane for cabin pressure and an outer structure to resist wing loads. A columned multi-bubble fuselage is proposed for the inner membrane structure, which are multispherical configuration to efficiently withstand the pressure loads. Considering this configuration, the carry-through structure can be designed and optimised. Finite element results show a significant reduction of stress level in this design over that for a conventional multi-bubble fuselage. Up to 30% weight reduction is achieved for a military cargo application that requires an extensive area with no structural interruption. For the outer carry-through structure, the topology and shape optimisations of finite element models were performed on the given design domain. The results from the shape and topology optimisations were complementary demonstrating a consistent design approach. The optimisation theory is briefly presented along with the results.
Guided bomb release planning based on Monte Carlo in a distributed virtual environment
Authors: Wang Z. , Wang J.
Published: February 2016

Air-to-ground strike has become one of main forms of modern warfare, and the guided bomb release is an important and key part of the attack. The guided bomb release planning aims to accomplish a precise target hit in enemy’s region while guarantee the pilot’s safety. We propose a robust Monte Carlo method by taking error perturbations into consideration, comparing to the traditional sequential quadratic programming method under extreme conditions. At the same time using a distributed virtual physics environment we can obtain much more detailed realism relative to the conventional simulator running on a single machine. The experimental results verify that Monte Carlo methods can improve hit probability and weapon efficiency significantly. Furthermore, the 3D visualised environment plays a very important role in training pilots, so this simulator will decrease the cost and time requirements of physical experiment that are not always compatible with strict military task.
Design, test and evaluation of an actively stabilised drogue refuelling system
Authors: Kuk T. , Ro K.
Published: February 2016

A scale model of aerial refuelling drogue is built and tested to investigate active drogue stabilisation and control concepts. A set of aerodynamic control surfaces is implemented to a conventional, aerodynamically stabilised refuelling drogue. The control surfaces are designed to reduce the response of the drogue motion to atmospheric disturbance and tanker motion. This paper presents the details of design concept and experimental results based on wind-tunnel testing of a ⅓ scale model fabricated for this study. To investigate the proposed active control concept, a dynamic test rig is built for wind-tunnel experiment. The rig basically represents a hose-drogue system in terms of a 4 degree-of-freedom (DoF), single link pendulum model. System identification technique is used to obtain a drogue dynamic model, based on which a feedback control law is developed. Closed-loop dynamic testing is carried out to evaluate the effectiveness of the aerodynamic surface control module and feedback control law.
On the effectiveness of active aeroelastic structures for morphing aircraft
Authors: Ajaj R. M. , Friswell M. I. , Flores E. I. Saavedra
Published: February 2016

This note assesses the benefits of active aeroelastic structures (AAS) in enhancing flight performance and control authority. A representative AAS concept, whose torsional stiffness and shear centre position can be altered depending on the instantaneous flight condition, is employed in the wing of a medium altitude long endurance (MALE) UAV. A multidisciplinary design optimisation (MDO) suite is used in this study. It turns out that AAS can be very effective when used for enhancing control authority of the vehicle but have limited benefits in terms of flight performance (lift to drag).
Is the effect of topical intranasal steroids on obstructive adenoids transient or long-lasting? Case series and systematic review of literature
Authors: Bitar M A , Nassar J , Dana R
Published: February 2016

Objectives:

To study and review the short- and long-term effects of intranasal steroids on obstructive adenoids.

Methods:

In this prospective cohort study, 19 children previously treated with mometasone furoate for 3 months were contacted at 3, 6 and 12 months after cessation of treatment. Main outcome measures included: change in severity of nasal obstruction, allergic rhinitis and obstructive symptoms. A systematic review of literature was also performed.

Results:

By one year, 25 per cent of patients required adenoidectomy; the remaining children had no significant change in clinical score (p= 0.464), obstruction severity (p= 0.191) or allergic symptoms (p= 0.284). Fourteen pertinent studies were identified; all but one study showed improvement in the patients’ symptoms and/or degree of obstruction. Two studies with follow up reaching 25 months showed positive effects.

Conclusion:

The short-term positive effect of some intranasal steroids on obstructive adenoids seems to persist in a significant number of patients after the cessation of treatment.
Connective processing by bilingual children and monolinguals with specific language impairment: distinct profiles
Authors: MAK WILLEM M. , TRIBUSHININA ELENA , LOMAKO JULIA , GAGARINA NATALIA , ABROSOVA EKATERINA , SANDERS TED
Published: February 2016

Production studies show that both Russian-speaking children with specific language impairment (SLI) and bilingual children for whom Russian is a non-dominant language have difficulty distinguishing between the near-synonymous connectivesi‘and’ anda‘and/but’.Iis a preferred connective when reference is maintained, whereasais normally used for reference shift. We report an eye-tracking experiment comparing connective processing by Russian-speaking monolinguals with typical language development (TLD) with that of Russian–Dutch bilinguals and Russian-speaking monolinguals with SLI (age 5–6). The results demonstrate that the processing profiles of monolinguals with TLD and bilinguals are similar: both groups use connective semantics immediately for predicting further discourse. In contrast, children with SLI do not show sensitivity to these semantic differences. Despite similar production profiles, bilinguals and monolinguals with SLI are clearly different in connective processing. We discuss the implications of these results for the possible causes of the errors in the two populations.
The Right To Be Different: Homosexuality, Orthodoxy And The Politics Of Global Legal Pluralism In Orthodoxprotestant Schools In The Netherlands
Authors: Oomen Barbara , Rijke Niels
Published: February 2016

In the summer of 2011, Dutch teacher Duran Renkema was dismissed from the orthodox Reformed school in Oegstgeest because he had left his wife and family, and decided to openly live together with his boyfriend. In the court case that followed, the judge ruled that the publicly funded denominational school did not have the right to dismiss a teacher who otherwise functioned well, merely because of his sexual identity. In collecting funds so it could take the case to the Equal Treatment Commission, the Dutch gay rights organization Coc emphasized that this was the first time that a teacher at a religious school publicly dared to contest his dismissal.

Although the teacher himself also initially threatened to put the issue before the Equal Treatment Commission (ETC), he later withdrew the case, stating, “my family, partner and I need rest to come to terms with what happened.” He indicated that he hoped that “the discussion and dialogue in the Reformed churches will not come to a halt here, but that they will take this opportunity to show the gay community in the Netherlands that the message in the Bible is one of love.
Battles Over Symbols: The “Religion” of the Minority Versus the “Culture” of the Majority
Authors: Beaman Lori G.
Published: February 2016

Moreover, with the benefit of hindsight, it is easy to identify in the constant central core of Christian faith, despite the inquisition, despite anti-Semitism and despite the crusades, the principles of human dignity, tolerance and freedom, including religious freedom, and therefore, in the last analysis, the foundations of the secular State.

A European court should not be called upon to bankrupt centuries of European tradition. No court, certainly not this Court, should rob the Italians of part of their cultural personality.

In March, 2011, after five years of working its way through various levels of national and European courts, the Grand Chamber of the European Court of Human Rights decided that a crucifix hanging at the front of a classroom did not violate the right to religious freedom under Article 34 of the Convention for the Protection of Human Rights and Fundamental Freedoms. Specifically, Ms. Soile Lautsi had complained that the presence of the crucifix violated her and her children's right to religious freedom and that its presence amounted to an enforced religious regime. The Grand Chamber, reversing the lower Chamber's decision, held that while admittedly a religious symbol, the crucifix also represented the cultural heritage of Italians.
Law, Religion, and Restorative Justice in New Zealand
Authors: Shriver Donald W. , Shriver Peggy L.
Published: February 2016

A former police chief and a criminologist confirm a famous remark by Margaret Mead when they write: “The initiation of restorative reforms is often based upon the conversion of one key professional in a criminal justice agency.”

New Zealand district court judge Fred W.M. McElrea personalized this rule in his account of how he stumbled on a restorative procedure in the case of a young man in Auckland, who was a Maori and son of a bishop, and who confessed to the crime of robbing a woman's purse. She happened to be a Quaker, and she appeared in court as a gesture of friendship for the offender. When the time came for sentencing, McElrea wondered out loud if there were a way for the young man to be monitored, without imprisonment, by some competent person who knew him. At that, Douglas Mansil, local Presbyterian minister, also present in the courtroom, stood and volunteered his services. Mansil had been the longtime “streetwise” pastor of a congregation in that Auckland neighborhood, known for furnishing the courts with more than a few youth offenders. Together with the Quaker victim of the crime, he kept track of the young man and reported regularly to the court. It was the beginning of McElrea's dedication to restorative justice (RJ) for young offenders in New Zealand. He and other judiciary leaders pay tribute to the influence of Howard Zehr's visit to New Zealand (NZ) in 1994 and Zehr's book, Changing Lenses, which McElrea first read during a sabbatical leave at Cambridge University. Zehr's book and his work in the U.S. had great impact on New Zealand legal officials, many of whom, like McElrea, often give him credit for inspiring shifts to RJ in their thinking about law, judicial process, and ethics.
The “Gatekeepers” of Jewish Family Law: Marriage Annulment as a Test Case
Authors: Westreich Avishalom
Published: February 2016

Jewish law is normally characterized by a pluralist discourse and, even when controversies are acrimonious, the merits of competitive arguments are recognized and receive some legitimacy. By contrast, Jewish family law, especially in the case of marriage annulment, is characterized quite differently, patently diverging from the pluralist hermeneutic discourse normally characterizing Jewish law. This divergence is the subject of this article.

From the work of early classic commentators to modern Jewish Law scholars, the character of marriage annulment in Jewish law has been much debated. Questions about both the authority of the Sages to annul a marriage and the meaning of annulment have arisen. Commentators have probed famous passages in the Babylonian Talmud mentioning the concept of marriage annulment (Heb. hafka'at kiddushin), often simply with the words “the Sages annulled the betrothal.” Similarly, discussing a case where a Jewish writ of divorce (get) was formally void but validated by the Sages, the Palestinian Talmud states “their [i.e., the Sages'] words uproot the words of the Torah,” which implies that the Sages have the authority according to Jewish law to annul a marriage in certain circumstances.
Religion in the Abortion Discourse in Singapore: A Case Study of the Relevance of Religious Arguments in Law-Making in Multi-Religious Democracies
Authors: Tan Seow Hon
Published: February 2016

I … appeal to hon. Members to face up to the challenge on this important social issue and give their full support to the Bill. I do hope that they will not falter just because of some pressure, social or otherwise, brought to bear on them by some minority groups outside who, on account of their religious dogmas, desire to impose their will on the majority… I am certain that the opposing stand to this Bill taken by this minority group will also in the course of time end up in the dustbins of history.

Abortion, along with same-sex unions, is perhaps one of the world's most polarizing issues today. Laws on abortion vary across different jurisdictions, from prohibiting abortion under all circumstances to freely allowing it without restriction as to reason. Unlike rights such as freedom from torture or of speech, failure to recognize abortion rights is not necessarily the product of illiberal governments known to abuse human rights, nor is allowing abortion indicative of a good human rights record. Extensive rights to terminate a pregnancy may be symptomatic of a government's policy for population control, as in the case of China, or it may be an expression of the liberal philosophy of autonomy, as in the case of Canada.