bluuebunny/crossref_metadata_2025 huggingface dataset:
A framework for environmental risk management
Authors: Lloyd S. , Clifton A. , Lee J. , Elghali L. , France C.
Published: February 2016

Aero engine designs can have a life time of over 45 years, which is long enough for the understanding of environmental problems to change significantly. This places the aero engine designer in a position of uncertainty, as unforeseen environmental problems could affect the viability of a design. ‘Risk’ is used to describe future uncertainties that can lead to undesirable consequences. This paper presents a framework for environmental risk management that allows the designer to answer the question: what is the risk to a design from its environmental impacts over the life cycle? The framework provides a process for turning complex environmental business hazards into a form that can be used to develop mitigating actions within the design process. The paper demonstrates the framework through two examples and discusses findings, leading to conclusions on what is required to implement the framework into a business.
The benefits and limitations of ground-based upset-recovery training for general aviation pilots
Authors: Rogers R. O. , Boquet A.
Published: February 2016

Research by Rogers et al (2009) and Leland et al established that flight simulator training can improve a pilot’s ability to recover a general aviation aeroplane from an in-flight upset. To reach this conclusion, they administered simulator-based and classroom-based upset-recovery training to two groups of student pilots, then compared their performance in recovering an aerobatic Decathlon aeroplane from a series of four upsets with the performance of a third group of untrained control group pilots subjected to the same upsets. We extend this result by addressing the unanswered question of how much classroom-based training as opposed to simulator-based training contributes to improving a pilot’s upset-recovery manoeuvring skills. After receiving classroom-based upset-recovery training but no simulator training, our participants were subjected to the same series of four upsets in the same Decathlon aeroplane. We then compared the performance of the classroom-trained pilots with the performances of control group pilots and the two groups of simulator-trained pilots. Statistical analysis suggests that classroom-based instruction alone improves a pilot’s ability to recover an aeroplane from an upset. We summarise related research, describe the training experiment and the training program, analyse and interpret flight-test data, and explain what our research implies with respect to establishing career-long commercial pilot upset-recovery training requirements.
Performance and control optimisations using the adaptive torsion wing
Authors: Ajaj R. M. , Friswell M. I. , Dettmer W. G. , Allegri G. , Isikveren A. T.
Published: February 2016

This paper presents the Adaptive Torsion Wing (ATW) concept and performs two multidisciplinary design optimisation (MDO) studies by employing this novel concept across the wing of a representative UAV. The ATW concept varies the torsional stiffness of a two-spar wingbox by changing the enclosed area through the relative chordwise positions of the front and rear spar webs. The first study investigates the use of the ATW concept to improve the aerodynamic efficiency (lift-to-drag ratio) of the UAV. In contrast, the second study investigates the use of the concept to replace conventional ailerons and provide roll control. In both studies, the semi-span of the wing is split into five equal partitions and the concept is employed in each of them. The partitions are connected through thick ribs that allow the spar webs of each partition to translate independently of the webs of adjacent partitions and maintain a continuous load path across the wing span. An MDO suite consisting of a Genetic Algorithm (GA) optimiser coupled with a high-end low-fidelity aero-structural model was developed and employed in this paper.
Analytical Volterra-based models for nonlinear low order flight dynamics approximation systems
Authors: Omran A. , Newman B.
Published: February 2016

Analytical methodology is presented to conduct dynamical assembly of simple low order nonlinear responses for system synthesis and prediction using Volterra theory. The procedure is set forth generically and then applied to several atmospheric flight examples. A two-term truncated Volterra series, which is enough to capture the quadratic and bilinear nonlinearities, is developed for first and second order generalised nonlinear single degree of freedom systems. The resultant models are given in the form of first and second kernels. A parametric study of the influence of each linear and nonlinear term on kernel structures is investigated. A step input is then employed to quantify and qualify the nonlinear response characteristics. Uniaxial surge and pitch motions are presented as examples of the low order flight dynamic systems. These examples show the ability of the proposed analytical Volterra-based models to predict, understand, and analyse the nonlinear aircraft behaviour beyond that attainable by linear-based models. The proposed analytical Volterra-based model offers an efficient nonlinear preliminary design tool in qualifying the aircraft responses before computer simulation is available or invoked.
The perforation resistance of sandwich structures subjected to low velocity projectile impact loading
Authors: Zhou J. , Guan Z. W. , Cantwell W. J.
Published: February 2016

This article presents the findings of a study to investigate the impact perforation resistance of sandwich structures. The dynamic response of sandwich panels based on PVC foam cores has been evaluated by determining the energy to perforate the panels. The impact response of the sandwich structures was predicted using the finite element analysis package Abaqus/Explicit. The validated FE models were also used to investigate the effect of oblique loading and to study the impact response of sandwich panels subjected to a pressure differential equivalent to flying at an altitude of 10,000m.

Low velocity impact testing has shown that the energy to perforate the sandwich panels is dependent on the properties of the core. It has been shown that increasing the density of the crosslinked PVC foams by a factor of two yielded a 600% increase in the perforation resistance of the sandwich structures. At higher densities, the crosslinked foam sandwich structures offered a superior perforation resistance to the linear PVC structures. The numerical analysis accurately predicted the perforation energies of the sandwich panels, as well as the prevailing failure mechanisms following impact. Finally, it has been shown that sandwich panels impacted at high altitude offer a similar perforation resistance to those tested at sea level.
Finite element modelling of sandwich panels with graded core under various boundary conditions
Authors: Kashtalyan M. , Woodward B.
Published: February 2016

Sandwich panels are widely used in the aerospace industry instead of solid plates due to their high flexural stiffness-to-weight and flexural strength-to-weight ratios. However due to the mismatch of properties between the face sheets and the core, stress concentrations can occur at the face sheet/core interfaces, often leading to delamination. One possible solution to this problem is the introduction of a graded core — a core in which the properties vary gradually from the face sheets to the core centre, eliminating any abrupt changes in properties. In this paper a 3D finite element method, fully validated through comparison with results from the literature and a 3D elasticity solution, is applied to modelling of sandwich panels with graded core. The approach makes use of graded elements to study the effect of varying the boundary conditions on the elastic deformation of the panel subject to uniformly distributed loading. Comparative analysis of stress and displacement fields in sandwich panels with homogeneous and graded cores is carried out under various combinations of simply supported, clamped and free edges.
Progressive failure analysis for the interaction of interlaminar and intralaminar failure modes in composite structures with an initial delamination
Authors: Ji W. , Waas A. M.
Published: February 2016

This paper is concerned with the development of a failure initiation and progressive failure analysis (PFA) method for advanced composite structures. The present PFA model is capable of predicting interactive out-of-plane and in-plane failure modes observed in fiber reinforced composite laminates including interlaminar behavior and matrix microdamage at the mesoscale. A probability analysis tool is coupled with the PFA to account for uncertainty in modelling parameters caused by material variability and manufacturing inconsistencies. The progressive damage response of a laminated composite panel with an initial delamination is studied and used to demonstrate the PFA modelling framework that is presented here.
Rapid, parallel CFD grid generation using octrees
Authors: Page G. J.
Published: February 2016

As Large Eddy Simulation is increasingly applied to flows containing complex geometry, grid generation becomes difficult and time consuming when using software originally developed for RANS flow solvers. The traditional ‘pipeline’ approach of grid generation → solve → visualise entails the time consuming transfer of large files and conversion of file formats. This work demonstrates a grid generation methodology developed specifically to be integrated with parallel LES. The current approach is to use a Cartesian grid with adaptive refinement based upon geometry intersection, surface detail and surface curvature. The grid is defined by an octree data structure with the geometry defined by triangular facets using the STL file format. The result is a set of ‘cubical’ subdomains, each with identical numbers of cells and uniform distributions within the cube. Some subdomains will be entirely fluid and can be solved using straightforward CFD techniques, whilst some cubes will be cut by the surfaces. Individual cells are then tagged as ‘solid’, ‘fluid’ or ‘cut’ with the solver expected to use an immersed boundary approach to model the surface. A key feature is the design of the algorithm to be parallelisable on both shared and distributed memory systems. The distributed memory parallel dynamically partitions the grid as it is being generated, so that the partitioning is suitable for a subsequent flow solver. Grid generation testing has been carried out on a variety of input CAD files ranging up to 350,000 facets. A landing gear case shows how the grid generator correctly finds the fluid inside of the tire and other cavities within the hub. In scalar mode, a grid with 4,916 cubes and 468 million cells is generated in less than 100 seconds, whilst in parallel on 32 processor cores this can be achieved in 4·6 seconds.
Supersonic flow over three dimensional cavities
Authors: Das R. , Kurian J.
Published: February 2016

This work presents a study of acoustic oscillations generated and the wave structure associated with supersonic flow past wall mounted 3D open cavities of varying length-to-width (L/W) ratio. Experiments were conducted to investigate the acoustic signature generated by the cavities at freestream Mach number of 1·7. The effect ofL/Wratio of the cavity on the dominant modes of the acoustic signature registered on different walls of the cavities is investigated for anL/Wrange of 0·83-4. Shift in the dominant acoustic mode is observed asL/Wratio changes from 3 to 4. Statistical analysis of pressure data showed existence of acoustic waves and spreading of acoustic energy over different modes with change in cavity width. Time averaged schlieren visualisation indicated variation of shock and shear layer structure in the mainstream for the different cavities. Acoustic waves generated by the presence of the cavity and the dynamic behaviour of the shear layer were observed during instantaneous shadowgraph visualisation. Numerical simulation was done to make a prior assessment of the flow structure and the results are in good agreement with those from experiments. Ratio of mass exchange between cavity and mainflow and the cavity volume was observed to have profound effect on the magnitude of pressure oscillations generated by the cavities.
Experimental investigation of the role of struts in high speed mixing
Authors: Desikan S. L. N. , Kurian J.
Published: February 2016

This paper presents the experimental results of the role of struts in supersonic mixing. Experiments were carried out with novel strut configurations to show their capabilities on mixing with reasonable total pressure losses. The performances were compared with the Baseline Strut configurations (BSPI and BSNI). The analysis presented includes the mixing quantifications using Mie scattering signature, flow field visualisation, measurement of wall static pressure and the total pressure loss calculations. The results clearly demonstrated that the proposed strut configurations achieved increased mixing (7-8%) compared to BSPI with increase in total pressure loss (2%). On the other hand, when compared with BSNI, the mixing performance was found to be decreased by 6% with reduced total pressure loss (12%).
Recent achievements in numerical simulation for aircraft power-plant configurations
Authors: Reneaux J. , Brunet V. , Esquieu S. , Meunier M. , Mouton S.
Published: February 2016

The engine/airframe integration design is one key differentiating factor for making efficient transport aircraft and this topic will become more important for future aircraft as the turbofan engine diameter is increased leading to a stronger engine-airframe interaction. Hopefully, the capabilities of advanced numerical simulations allow the involved complex phenomena to be taken into account and this is illustrated in this paper through several research studies: the use of the Reynolds averaged Navier-Stokes equations together with the drag extraction techniques to predict the drag, the simulation of unsteady complex interaction between the jet and the pylon with the zonal detached eddy simulation method, the pylon and nacelle design through multi disciplinary optimisation and the flow control technologies.
Assessment of surface roughness for a ‘silent’ aircraft
Authors: Liu Y.
Published: February 2016

Boundary-layer noise produced by rough surfaces is a potential contributor to airframe noise. In this paper, an attempt is made to assess the surface roughness noise for a conceptual Silent Aircraft design SAX-40 using a prediction model described in previous theoretical work (Liu and Dowling(12)). Estimates of three idealised test cases show that surface roughness could produce a relatively high noise level and enhance the trailing-edge noise somewhat. Roughness height and roughness density are two significant parameters which affect surface roughness noise, with roughness height having the more dominant effect. The distribution of roughness noise sources decreases in the streamwise direction on the SAX-40 surface. Two candidate rough surfaces are selected for SAX-40 to keep surface roughness noise at a negligible level and to meet an aggressive noise target.
Roll control of a MALE UAV using the adaptive torsion wing
Authors: Ajaj R. M. , Friswell M. I. , Dettmer W. G. , Isikveren A. T. , Allegri G.
Published: February 2016

This paper assesses the feasibility of the Adaptive Torsion Wing (ATW) concept to replace conventional ailerons and enhance the manoeuvrability of a MALE UAV. The ATW concept is a thin-walled closed section two-spar wingbox whose torsional stiffness can be adjusted through the chord-wise position of the front and rear spar webs. The reduction in torsional stiffness allows external aerodynamic loads to induce aeroelastic twist that can be used as a function of the flight conditions to obtain a desired roll control authority. Modelling of the concept was performed using a conceptual design tool developed in MATLABTM. The variation of structural figures of merit are evaluated and discussed. Finally, an MDO study was performed to have in-depth assessments of the potential benefits of the ATW in replacing ailerons and providing sufficient roll control.
Aerodynamic performance benefits of utilising camber morphing wings for unmanned air vehicles
Authors: Naranjo A. García , Cowling I. , Green J. A. , Qin N.
Published: February 2016

This work considers the effects of camber morphing, both in magnitude and chord position, on the performance of a generic unmanned air vehicle (UAV). The focus is to maximise appropriate aerodynamic factors across the mission by optimising the wing camber. Specifically, the enhancement of range, endurance, and stall speed is sought by means of maximising their aerodynamic performance parameters, CL/CD, CL3/2/CD, and CLmax respectively. An analysis of the effects of camber morphing is carried out using the vortex panel code, XFOIL, utilising aerofoils from the NACA four-digit family. The results are then adjusted to account for 3D flow factors such as induced drag, offering a more realistic appraisal of their effectiveness. Flight testing is then performed on four wings of fixed aerofoil sections, optimised for each performance characteristic, to validate the trends observed in the XFOIL data onboard a 1·64m span aircraft.
Panel method predictions of added mass for flexible airship
Authors: Zhang M. , Wang X. , Duan D.
Published: February 2016

Because of the huge volume and inflated membrane structure of stratosphere airship, the deformation of stratosphere airship is very sensitive to the change of environment conditions such as wind, temperature and so on. The influence of deformation on manipulation and control is very remarkable. So, during the course of building flight dynamic model of the flexible airship, the added-mass matrix of deformation is very important part in the state equations of dynamic models. For obtaining the accurate added-mass matrix of different flexible airship, we proposed an approach that can calculate the added-mass matrix of a flexible airship with arbitrary geometry shape by the panel method. Through the comparison of results of computation and theory for ellipsoid of revolution and the flexible Skyship-500 airship, the proposed method can calculate the added-mass matrix for arbitrary geometric shape very accurately.
Hypersonic minimum drag forebodies with blunt leading edges
Authors: Pike J.
Published: February 2016

The minimum pressure drag of blunt forebodies in hypersonic flow is investigated using Newton’s Impact Theory. It is shown how the minimum drag shape varies with the body slenderness and the amount of blunting. As the blunting increases the drag approaches that of the minimum drag axisymmetric body.
Flow features around double cones at hypersonic speed
Authors: Gomes-Fernandes R.
Published: February 2016

An experimental study of double cone geometries in hypersonic flow (at M∞ of 8·2 and Red of 0·36 × 106) was performed to provide additional data to a computational simulation study. In this study, depending on how the flow was initialised, the numerical solution yielded a violent pulsation mode of instability or a steady flow. Finally, an analysis of the shock oscillation was made and discussed.
Multidisciplinary optimisation framework for minimum rotorcraft fuel and air pollutants at mission level
Authors: Linares C. , Lawson C. P. , Smith H.
Published: February 2016

Helicopters play a unique role in modern aviation providing a varied range of benefits to society and satisfying the need for fast mobility. However, environmental concerns associated with the operation of rotorcraft have increased due to envisaged growth of helicopter operations. New rotorcraft designs, innovative aero engines and all-electrical systems, which may take decades to be in service, are being developed in order to diminish rotorcraft footprint on environment. However, since there is a large number of polluting rotorcraft that are in use and will only gradually be replaced, in the near-term, improvements to minimise air quality degradation may also be possible from better use of existing rotorcraft by focusing on mission profile management. A multidisciplinary framework, intended to generate outputs for estimating rotorcraft block fuel burn and emissions, was developed. Outcomes generated with this tool were, subsequently, the basis to carry out a parametric study for assessment of light single-engine rotorcraft environmental impact, in terms of fuel burn and emissions. Single and multi-objective optimisation for minimum fuel consumption and air pollutant emissions was part of this research as well.
New altitude optimisation algorithm for the flight management system CMA-9000 improvement on the A310 and L-1011 aircraft
Authors: Patrón R. S. Félix , Botez R. M. , Labour D.
Published: February 2016

The current flight management system (FMS), CMA-9000, from CMC Electronics-Esterline, only optimises the vertical flight profile in terms of the speed of the aircraft. This article defines a methodology that optimises the speeds and altitudes for the vertical profile, obtaining a trajectory that reduces the global flight cost.

The performance database (PDB) provided by CMC Electronics-Esterline is presently used on aircraft such as the Lockheed L-1011, the Airbus A310 and the Sukhoi Superjet 100 Russian regional jet. The PDB is used as the reference to design different trajectory optimisation algorithms to obtain the altitude where the aircraft fuel efficiency is the best. These algorithms are compared with the part-task trainer (PTT), simulator that represents the FMS CMA-9000, supplied by CMC Electronics-Esterline as well.

To validate the results, the FlightSIM® software is used, which considers a complete aircraft aerodynamic model for its simulations, giving accurate results and very close to reality.
Constrained large angle reorientation manoeuvres of a space telescope using potential functions and a variable control gain
Authors: Mengali G. , Quarta A. A.
Published: February 2016

In some space applications, such as satellite surveillance and communication, a spacecraft must perform accurate pointing and slewing manoeuvres, whereby the spacecraft is rotated along a large angle amplitude trajectory. In many circumstances it is also required that the sensitive payload does not intercept bright objects such as the Sun, Earth and Moon, to avoid possible damage to the optical instruments. The importance of this subject has stimulated an active research, and different approaches have been reported in the literature(1-5).
Application of the weight function method on a high incidence research aircraft model
Authors: Anton N. , Botez R. M. , Popescu D.
Published: February 2016

This paper assesses the application of a new method for system stability analysis, the weight functions method, to the longitudinal and lateral motions of a High Incidence Research Aircraft Model. The method consists of finding the number of weight functions that is equal to the number of differential equations required for system modelling. The aircraft’s stability is determined from the sign of the total weight function; which should be negative for a stable model. The Aero-Data Model In Research Environment (ADMIRE) simulation, developed by the Swedish Defence Research Agency, was used for the aerodynamic aircraft modelling, with the following configurations: Mach number = 0·25, altitude = 500m, angle-of-attack [–10 to 30]°, elevon deflection angle [–30 to 30]°, canard deflection [0° and 25°] and rudder deflection angles [–30° and 30°]. These flight configurations were selected because they are among the flight conditions for Cat. II Pilot Induced Oscillation (PIO) criteria validation, performed on the FOI aircraft model presented in the PIO Handbook by the Group for Aeronautical Research and Technology in Europe, Flight Mechanics/Action Group 12. This aircraft model has a known instability for longitudinal and lateral motions and so a control law was introduced to stabilise its flight.
A study of mixed-mode composite delamination using enriched interface elements
Authors: Guiamatsia I. , Ankersen J. K. , Iannucci L.
Published: February 2016

This paper examines the performance of enriching the shape functions of interface finite elements in the prediction of mixed-mode delamination. Enriching second-order interface and solid elements with the analytical solution of a beam on elastic foundation problem yields the correct displacement field ahead of the crack tip. Despite the enrichment being fixed at elements nodes, resulting in non-traceability of the crack tip location, the strategy is shown to perform consistently well, increasing the minimum element size from the typical 0·5mm to 5mm, for a range of classical mixed-mode bending (MMB) specimens.
The influence of transition onset location on the performance of shock control bumps
Authors: McIntosh S. C. , Qin N.
Published: February 2016

In order to investigate the robustness of three dimensional bumps on shock control for natural laminar-flow wings, the impact of transition onset location on the overall performance of the shock control device was studied. For a ramp bump, a moderate ramp start angle θr =4° was found to effectively fix the location of the leading leg of the shock lambda, decreasing chord-wise movement in the main shock position resulting from variations in transition onset location. With increasing transition onset length from xtrans =0% chord to 45% chord, little influence was found regarding the overall performance of the shock control device but a down-stream movement of the secondary leg of the shock lambda in a range about 3% chord was observed. Change in the boundary-layer displacement thickness due to varying transition onset locations was identified as the primary mechanism responsible for this secondary shock leg movement.
Effect of change in role of an aircraft on engine life
Authors: Gad-Briggs A. , Haslam A. , Laskaridis P.
Published: February 2016

New aircraft require years of development from concept to realisation and can be prone to delays. Consequently, military operators take existing fleets and operate them in a different role. The objective of this study is to examine the effect of operating a typical low bypass military fast jet engine, originally designed for a European theatre, in a hot and harsh climate. The specific purpose is to determine the effect on the high-pressure turbine blade life and the life- cycle cost of the engine.

A mission profile and respective performance conditions were analysed and modelled using an in-house performance tool. The flow conditions were simulated using ANSYS® FLUENT. A conjugated heat transfer solution was adopted to determine the blade metal temperature. The blade was modelled physically in 3D using SIMULIA® ABAQUS FEA software. The stresses were derived and used to calculate the temperature coupled low cycle fatigue and creep life.

A deterioration case was also studied to evaluate the effect of sand and dust ingestion. There was a significant life reduction of approximately 50% due to creep. The reduction in life was inversely proportional to the life cycle cost of the engine depending on the operating conditions. The results were compared with similar engines and summarised in the context of airworthiness regulations and component integrity.
A virtual test environment for validating spacecraft optical navigation
Authors: Parkes S. M. , Martin I. , Dunstan M. N. , Rowell N. , Dubois-Matra O. , Voirin T.
Published: February 2016

The use of machine vision to guide robotic spacecraft is being considered for a wide range of missions, such as planetary approach and landing, asteroid and small body sampling operations and in-orbit rendezvous and docking. Numerical simulation plays an essential role in the development and testing of such systems, which in the context of vision-guidance means that realistic sequences of navigation images are required, together with knowledge of the ground-truth camera motion. Computer generated imagery (CGI) offers a variety of benefits over real images, such as availability, cost, flexibility and knowledge of the ground truth camera motion to high precision. However, standard CGI methods developed for terrestrial applications lack the realism, fidelity and performance required for engineering simulations.

In this paper, we present the results of our ongoing work to develop a suitable CGI-based test environment for spacecraft vision guidance systems. We focus on the various issues involved with image simulation, including the selection of standard CGI techniques and the adaptations required for use in space applications. We also describe our approach to integration with high-fidelity end-to-end mission simulators, and summarise a variety of European Space Agency research and development projects that used our test environment.
Optimal aircraft take-off with thrust vectoring
Authors: Vinayagam A.K. , Sinha N.K.
Published: February 2016

The short take-off capability is of paramount importance for a fighter airplane to enable its operation from short and damaged runways. This paper analyses the airplane take-off process from the viewpoint of reducing the ground roll/take-off distance with the use of thrust vectoring. The airplane take-off is modelled incorporating the ground reactions on the landing gear and the thrust vector forces and moments. The take-off problem is formulated as an optimal control problem with appropriate constraints. Though many researchers have applied optimal control techniques for designing airplane manoeuvres, its application to the airplane take-off problem is rarely available in the open literature. It is expedient to use such methodology to understand the use of thrust vectoring features of an aircraft to maximise the benefits in shortening the ground roll/take-off distance. An optimal control methodology has been applied in this paper with the objectives stated above to a twin-engine fighter nonlinear aircraft model popularly known as F-18/HARV. Computation of flight path and control schedules using optimal control has been carried out with and without the use of vector nozzles. A reduction of about 6% in take-off distance and about 29% in ground roll distance is obtained with the use of thrust vector for the configuration studied.
The use of topology optimisation in the conceptual design of next generation lattice composite aircraft fuselage structures
Authors: Niemann S. , Kolesnikov B. , Lohse-Busch H. , Hühne C. , Querin O. M. , Toropov V. V. , Liu D.
Published: February 2016

Conventional commercial aircraft fuselages use all-aluminium semi-monocoque structures where the skin carries the external loads, the internal fuselage pressurisation and is strengthen using frames and stringers. Environmental and economic issues force aircraft designers to minimise weight and costs to keep air transport competitive and safe. But as metal designs have reached a high degree of perfection, extraordinary weight and cost savings are unlikely in the future. Carbon composite materials combined with lattice structures and the use of topology optimisation have the potential to offer such weight reductions. The EU FP7 project Advanced Lattice Structures for Composite Airframes (ALaSCA) was started to investigate this. This article present some of this research which has now led to the development of a new airframe concept which consists of: a load carrying inner skin; transverse frames; CFRP-metal hybrid stiffeners helically arranged in a grid configuration; insulating foam and an additional aerodynamic outer skin.
The virtual AirDyn: a simulation technique for evaluating the aerodynamic impact of ship superstructures on helicopter operations
Authors: Kääriä C. H. , Forrest J. S. , Owen I.
Published: February 2016

This paper describes a simulation technique that has been developed to quantify the unsteady forces and moments that are imposed onto a maritime helicopter by a ship’s airwake during a deck landing. An unsteady CFD-generated airwake, created using a CAD model of the ship, is integrated with a flight dynamics model of a helicopter. By holding the helicopter at a fixed position in the airwake it is possible to quantify the unsteady forces and moments imposed on the aircraft. The technique is therefore a software-based airwake dynamometer, and has been called the virtual AirDyn. As well as determining the mean loads, from consideration of the unsteady loads in the closed-loop pilot response frequency range of 0·2-2Hz it is also possible to quantify the magnitude of the unsteady disturbance in each axis. The loads are also indicators of the control activity the pilot would have to exert to maintain aircraft position and attitude. By placing the virtual AirDyn at different positions around the landing deck in different wind conditions, it is able to quantify the effect of the airwake on the mean and unsteady loads. The quantified loads can be explained by examining the CFD-generated flow field, and the geometric features on the ship’s superstructure that gave rise to them can be identified. The virtual AirDyn is therefore a tool that can be used to evaluate and inform ship design for maritime helicopter operations.
Preliminary design and performance analysis of a low emission aero-derived gas turbine combustor
Authors: Khandelwal B. , Karakurt A. , Sethi V. , Singh R. , Quan Z.
Published: February 2016

Modern gas turbine combustor design is a complex task which includes both experimental and empirical knowledge. Numerous parameters have to be considered for combustor designs which include combustor size, combustion efficiency, emissions and so on. Several empirical correlations and experienced approaches have been developed and summarised in literature for designing conventional combustors. A large number of advanced technologies have been successfully employed to reduce emissions significantly in the last few decades. There is no literature in the public domain for providing detailed design methodologies of triple annular combustors.

The objective of this study is to provide a detailed method designing a triple annular dry low emission industrial combustor and evaluate its performance, based on the operating conditions of an industrial engine. The design methodology employs semi-empirical and empirical models for designing different components of gas turbine combustors. Meanwhile, advanced DLE methods such as lean fuel combustion, premixed methods, staged combustion, triple annular, multi-passage diffusers, machined cooling rings, DACRS and heat shields are employed to cut down emissions. The design process is shown step by step for design and performance evaluation of the combustor.

The performance of this combustor is predicted, it shows that NOxemissions could be reduced by 60%-90% as compared with conventional single annular combustors.
Numerical simulation of fluid-structure interaction in the opening process of conical parachute
Authors: Cao Y. , Wu Z. , Song Q. , Sheridan J.
Published: February 2016

According to multi-node model, the dynamics equations of conical parachute system for simulating shape deformation process of the flexible canopy in the opening process were established. With the combination of dynamics equations code and computational fluid dynamics (CFD) software, the fluid-structure interaction investigation of the conical parachute was carried out. Also the change of parachute shape and flow field, inflation time, the rate of descent, the distance of descent, and other relevant data were achieved. This paper has focused on analysing vortex structure of the flow field in the opening process of conical parachute, and laid the foundation for studying mechanics mechanism of flow field variation of conical parachute in future.
Aeroelastic analysis through linear and non-linear methods: a summary of flutter prediction in the PUMA DARP
Authors: Taylor N. V. , Allen C. B. , Gaitonde A. L. , Jones D. P. , Vio G. A. , Cooper J. E. , Rampurawala A. M. , Badcock K. J. , Woodgate M. A. , Henshaw M. J. de C.
Published: February 2016

This paper presents a comparison of linear and non-linear methods for the analysis of aeroelastic behaviour and flutter boundary prediction. The methods in question include NASTRAN and ZAERO, based on linear aerodynamics, and the non-linear coupled CFD-CSD methods RANSMB and PMB, developed at the Universities of Bristol and Glasgow respectively. The test cases used for this comparison are the MDO and AGARD 445.6 weakened wing. In general, it was found that the non-linear methods demonstrate excellent agreement with respect to pressure distributions, deflections, dynamic behaviour, and flutter boundary locations for both cases. This is in contrast to previous studies involving similar methods, where notable differences across the MDO span were found, and is taken to imply good performance of the CFD-CSD interpolation schemes employed here. While the linear methods produce similar flutter boundaries to the coupled codes for the aerodynamically simple AGARD 445.6 wing, results for the transonic ‘rooftop’ MDO wing design did not agree as well.
First Nations, Citizenship and Animals, or Why Northern Indigenous People Might Not Want to Live in Zoopolis
Authors: Nadasdy Paul
Published: February 2016

Recent northern First Nation land claim agreements have created a new category of First Nation citizenship. Although many embrace the category as an essential aspect of First Nation sovereignty, others reject it as a colonial imposition that constrains the possibilities for indigenous politics. There does indeed appear to be a gap between the legal category of First Nation citizenship and northern indigenous peoples’ ideas about political society. For one thing, the latter includes animals, while the former does not. In their recent book,Zoopolis, Donaldson and Kymlicka develop a model of animal citizenship. Although not primarily concerned with First Nation citizenship, they do assert the universality of their model, including its compatibility with indigenous ideas about proper human-animal relations. In this article, I assess those claims and show that, to the contrary, their model is in many ways antithetical to the knowledge and practices of northern indigenous peoples.
Skin in the Game versus Skimming the Game: Governance, Share Restrictions, and Insider Flows
Authors: Ozik Gideon , Sadka Ronnie
Published: February 2016

This paper advances the proposition that share restrictions engender potential conflicts of interest between fund managers and investors. Fund flows predict future fund returns for share-restricted funds, especially among funds with low levels of governance and funds managing insiders’ wealth, providing managers incentive to trade in advance of their clients. Some direct evidence for such managerial action is presented, using proprietary data on managerial investment in their own funds. The evidence suggests that private information about a fund, not necessarily its holdings, may constitute material information, with implications for proper fund governance and disclosure policy concerning managerial actions.
A new species ofParaglypturus(Crustacea: Decapoda: Axiidea: Callianassidae) from a vent field in the Tonga Arc of the south-western Pacific Ocean
Authors: Ahn Dong-Ha , Kim Se-Joo , Ju Se-Jong , Min Gi-Sik
Published: February 2016

A new species of callianassid ghost shrimp,Paraglypturus tonganussp. nov., is described and illustrated on the basis of five specimens that were collected from sediments in a vent field of the Tonga Arc, south-western Pacific Ocean. This new species is morphologically very similar toP. calderusTürkay & Sakai, 1995, the type species of the genusParaglypturusTürkay & Sakai, 1995. It differs fromP. calderusmainly in the absence (vs. presence inP. calderus) of an anterolateral row of setal pores on the carapace; the endopod of the second maxilliped, with a dactylus bearing stiff and thick serrate setae at the apex (vs. without inP. calderus); a yellow circular structure located on the ventral surface on the uropodal endopod (vs. on the dorsal surface on the uropodal exopod inP. calderus); and the articulation structure of the first pleopod in males (uniarticulate inP. tonganusvs. biarticulate inP. calderus). The new species is the first record of a ghost shrimp from a vent field of the Tonga Arc, and also the second reported species of the genusParaglypturus.
The Reality of Moral Imperatives in Liberal Religion
Authors: Lesnick Howard
Published: February 2016

God has made man with the instinctive love of justice in him,

which gradually gets developed in the world …. I do not pretend

to understand the moral universe; the arc is a long one, my eye

reaches but little ways; I cannot calculate the curve and complete

the figure by the experience of sight; I can divine it by conscience.

And from what I see I am sure it bends towards justice.

Theodore Parker (1853)

A strange mystery it is that Nature, omnipotent but blind, in the

revolutions of her … hurryings through the abysses of space, has

brought forth at last a child, subject still to her power, but gifted

with sight, with knowledge of good and evil, with the capacity of

judging all the works of his unthinking mother. [Gradually, as

morality grows bolder, the claim of the ideal world begins to be

felt, [giving rise to the claim] that, in some hidden manner, the

world of fact is really harmonious with the world of ideals. Thus

man creates God, all-powerful and all-good, the mystic unity of

what is and what should be.
Seeking to Accommodate Shari'a Within A Human Rights Framework: The Future of The Greek Shari'A Courts
Authors: Tsitselikis Konstantinos
Published: February 2016

The Balkans, a region where Christianity and Islam have come into close contact since before World War Ii, is an interesting study in legal pluralism. Themillet system, under which distinct ethnic-religious communities including Muslims were granted partial institutional autonomy, was at that time a convenient legal paradigm to accommodate minorities within the new national states being created. However, the communist regimes that succeeded the War in the Balkans eradicated legal pluralism in favor of a uniform legal order. As a consequence, the authority to employshari'ain Muslim communities in this region was abolished under communism.

The political changes occurring in the Balkans after communism was dismantled in the 1990s did not bring back theshari'acourts in most of the Balkans. However, Greece, having escaped these radical political shifts, retained a continuous legal regime that included some legal autonomy granted to the Greek Muslim population that survived a population exchange with Turkey at the end of the Greek-Turkish war of 1919-1922. As a result of the Lausanne treaty, the Muslim population of (Western) Thrace in Greece was granted a special minority protection regime that appliedshari'alaw to Muslim Greek citizens residing in that region of Thrace. However,shari'ais only applied to certain disputes of family and inheritance law by the localMuftiin Western Thrace who has special jurisdiction over these matters.
Rape as a variant of fornication(Zinā)Inislamic Law: An Examination of the Early Legal Reports
Authors: Azam Hina
Published: February 2016

The contemporary treatment of rape in the penal codes of Muslim nations has come under increasing scrutiny over the last two decades, as several high-profile cases have arisen in which women have claimed sexual assault but been unable to bring sufficient proof of non-consent. In some cases, claimants have subsequently been punished for fornication (zinā) because their accusations were seen as constituting confession to consensual illicit sex, while in other cases, a resulting pregnancy has been taken as evidence of the same. These cases have illustrated the particular problems that stem from defining rape as a coercive variant of fornication, orzinā.

These cases have largely arisen in the context of national efforts to Islamize the legal code by bringing laws into line with perceivedsharī'aguidelines. This slew of cases has prompted journalists, human rights groups and Muslim reformers to ask whether contemporary “Islamic” rape laws are really continuous with the classical Islamic juristic tradition, or whether they may in fact represent distortions of that tradition. A central point of debate has been over whether Islamic juristic discourse truly placed rape—that is, a man's unlawful sexual intercourse with a woman against her will—under the category ofzinā, or not.
The Relevance of aMaqasidApproach for Political Islam Post Arab Revolutions
Authors: Rane Halim
Published: February 2016

The role of Islam in the politics of Muslim-majority countries has attracted a plethora of scholarly research over the past two decades that generally refers to this phenomenon as political Islam. Much of the focus of this body of literature is concerned with the reconciliation of Islam and democracy. In recent years, the leading scholarship in this field has attempted to anticipate the future of political Islam and the prospect of post-Islamism. Asef Bayet's work on post-Islamists examines various social movements in the Middle East, arguing that Muslims have made Islam democratic by how they have defined Islam in respect to their particular socio-political contexts. However, others have expressed pessimism about the extent to which domestic conditions in Muslim-majority countries and external geopolitical factors will allow the development of an Islamic democracy. Abdelwahab El-Affendi, for instance, sees four main options for Islamists: full revolutionary takeover of their respective countries; completely withdrawing from political office to become Islamic interest or pressure groups; building broader coalitions while maintaining their ideology; or radically restructuring in order to emulate the model of Turkey's Justice and Development Party (AKP). What is missing in this discussion is attention to the capacity of Islamic political parties to draw on Islamic tradition and evolve in response to modernity through a focus on Islam's higher objectives or amaqasidapproach.
God and War: An Exploration
Authors: Eberle Christopher J.
Published: February 2016

In this article, I intend to explore the normative relation(s) between “God” and “war.” A bit more precisely, I intend to explore the normative relevance of theistic conviction to the proper employment of military violence. Even more precisely, I intend to explore the relevance of theistic conviction to the proper employment of military violence as judged by the so-called Just War Tradition (JWT). Properly interpreted, I take the JWT to provide the best available account of the morality of war. The JWT is not perfect and is bedeviled by serious problems, but it is the best available nonetheless. So, when I reflect on the morality of war, and thus on the normative relation(s) between religion and war, I do so from the perspective of the JWT.

Now this might seem to portend a very brief discussion. As we will see in detail, contemporary adherents typically construe the JWT in resolutely secular terms. Perhaps in order to compensate for its religious prehistory, most insist that the JWT has outgrown its religious provenance and may not be used to legitimate a crusade, ajihad, a holy war, or anything of the sort. In so doing, they align the JWT with the commonplace, endemic to contemporary liberal democracies, that religious wars and religious justifications for war lay far, far beyond the moral pale.