bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal wing twist distribution for roll control of MAVs
Authors: Ahmed M. R. , Abdelrahman M. M. , ElBayoumi G. M. , ElNomrossy M. M.
Published: February 2016

The aerodynamic design optimisation of a Micro Air Vehicle (MAV) wing is performed to obtain the optimal anti-symmetric wing twist distribution for the roll control of the MAV’s wing instead of using conventional ailerons. This twist distribution should produce minimum induced drag and achieve a better roll response. The implementation of several anti-symmetric load distributions such as the half lemniscates and the Horten distributions is studied leading to an initial solution for the optimal distribution that could achieve better roll requirements. Multhopp’s method based on Prandtl’s classical lifting line theory is used for the determination of the spanwise load distribution required during the optimisation process. The optimisation process is based on the modified feasible directions gradient based optimisation algorithm implemented in the optimisation system, VisualDOC, given by Dr. Garret Vanderplaats. The proposed optimisation process is applied to the ‘BARQ’developed MAV which has successful flight in July 2009.
Design, analysis and experimental validation of a morphing UAV wing
Authors: Bolinches M. , Keane A. J. , Forrester A. I. J. , Scanlan J. P. , Takeda K.
Published: February 2016

The design of wings with morphing capabilities is known to give aerodynamic benefits. These aero-dynamic benefits come from both the use of hinge-less surfaces and the greater adaptability to flight conditions. This paper describes the structural design of a twisting wing to be used for an unmanned air vehicle (UAV) and presents finite element analysis and experiment results. This is part of a research project carried out at the University of Southampton in which one of the goals is to compare different novel wing designs and technologies to determine which one of them gives the best performance. The twisting capability provides roll control without hinged surfaces hence providing aerodynamic improvement. The wing is manufactured using polystyrene foam and is cut out of block of this material using a hot wire machine. In order to link this foam structure to a main spar, ABS plastic inserts were manufactured using a 3D printer. The mechanisms used to actuate the wing are also made from this material. A full scale UAV wing has been manufactured and tested in order to compare with FEA results.
A career in vortices and edge forces
Authors: Lamar J.
Published: February 2016

This lecture recognises the background and distinguished work of Frederick William Lanchester, and notes that my background has a few similarities with his. These include a shared interest in wings, lift and vortices. My career at the NASA Langley Research Center spans the time-frame from America’s Super Sonic Transport through 2009. An early emphasis involved wind-tunnel testing of research aircraft models and the development of computer codes for subsonic aerodynamics of wing planforms. These attached-flow codes were applied to various configurations, including those with variable-sweep, dihedral, and more than one planform in both the analysis- and design-modes. These codes were used to provide a connection between leading-edge-forces and the associated additional lift on delta-wings with shed-vortex systems through the leading-edge suction analogy of Edward C. Polhamus. Subsequently, I extended the suction analogy to configurations with side-edges to predict the vortical-flow aerodynamics on complex configurations, including wing-strake combinations. These analysis codes could also be used in a design-by-analysis mode for configurations with leading-edge shed vortices. Later, I was involved in vortical-flow flight research with the F-106B and the F-16XL aircraft at cruise and maneuver conditions. Associated CFD predictions, generated by me and other members of the RTO/AVT-113 task group, have increased our understanding of the flight flow-physics measured on the F-16XL aircraft.
Numerical investigation of optimal pin location on a supersonic projectile
Authors: Bell M. , Robinson T. D. , Robinson D.
Published: February 2016

The flowfield around a supersonic projectile using a pin actuator control method has been predicted using computational fluid dynamics. It has been predicted using both viscous and inviscid methods for a number of positions. Both methods showed that an optimal longitudinal position exists. However, the inviscid model over-predicted the lateral acceleration due to the difference in shock formation around the pin between the two approaches. The optimal location was predicted independent of solver, however the higher-fidelity solver predicted lower achievable lateral accelerations. This is due to the viscous interactions caused by the pin. The effect of projectile orientation has shown that shielding the pin leads to reduced effectiveness due to the wake of the fin enveloping the pin. When the pin is exposed to onset flow, the forces achieved are increased. There is also an increase in the achievable forces and moments with increasing Mach number.
A hybrid fuzzy logic proportional-integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy Part 2: Controller implementation and validation
Authors: Grigorie T. L. , Botez R. M. , Popov A. V. , Mamou M. , Mébarki Y.
Published: February 2016

The paper presents the numerical and experimental validation of a hybrid actuation control concept – fuzzy logic proportional-integral-derivative (PID) plus conventional on-off – for a new morphing wing mechanism, using smart materials made of shape memory alloy (SMA) as actuators. After a presentation of the hybrid controller architecture that was adopted in the Part 1, this paper focuses on its implementation, simulation and validation.

The PID on-off controller was numerically and experimentally implemented using the Matlab/Simulink software. Following preliminary numerical simulations which were conducted to tune the controller, an experimental validation was performed. To implement the controller on the physical model, two programmable switching power supplies (AMREL SPS100-33) and a Quanser Q8 data acquisition card were used. The data acquisition inputs were two signals from linear variable differential transformer potentiometers, indicating the positions of the actuators, and six signals from thermocouples installed on the SMA wires. The acquisition board’s output channels were used to control power supplies in order to obtain the desired skin deflections. The experimental validation utilised an experimental bench test in laboratory conditions in the absence of aerodynamic forces, and a wind-tunnel test for different actuation commands. Simultaneously, the optimised aerofoils were experimentally validated with the theoretically-determined aerofoils obtained earlier. Both the transition point real time position detection and visualisation were realised in wind tunnel tests.
Camera tracking and qualitative airflow assessment of a two-turn erect spin
Authors: Hoff R. I. , Gratton G. B.
Published: February 2016

Motion and airflow during a two-turn erect spin of an aerobatic light aeroplane have been analysed. An alternative method, based upon camera tracking, has been used to capture the spin motion. A CAD model of the Slingsby Firefly was created using laser scanning. Formation flights with a helicopter have been flown and high-quality video and still imagery obtained. Camera tracking has produced data and unique illustrations of the spinning Slingsby. To further investigate the aerodynamic flow of a spinning aeroplane, full-scale, flow visualisation flights have been flown using wool tufts on wing, fuselage and empennage. Tufts indicate that a large vortex forms on the outside wing. The spanwise motion of this vortex has been studied and related to the spin motion. Furthermore, tufts on the horizontal tail indicate the presence of a leading edge vortex with the flow mainly in a spanwise outwards direction. The effects observed are clearly three dimensional and time dependent. Finally, it is discussed how this new knowledge does not correspond with the spin theories of the past.
On the generation of the mean velocity
profile for turbulent boundary layers with pressure
gradient under equilibrium
conditions
Authors: Rona A. , Monti M. , Airiau C.
Published: February 2016

The generation of a fully turbulent boundary layer
profile is investigated using analytical and
numerical methods over the Reynolds number range 422
≤ Reθ ≤ 31,000. The numerical method uses
a new mixing length blending function. The
predictions are validated against reference wind
tunnel measurements under zero streamwise pressure
gradient. The methods are then tested for low and
moderate adverse pressure gradients. Comparison
against experiment and DNS data show a good
predictive ability under zero pressure gradient and
moderate adverse pressure gradient, with both
methods providing a complete velocity profile
through the viscous sub-layer down to the wall.
These methods are useful computational fluid dynamic
tools for generating an equilibrium thick turbulent
boundary layer at the computational domain
inflow.
Surrogate based design optimisation of composite aerofoil cross-section for helicopter vibration reduction
Authors: Murugan M. S. , Ganguli R. , Harursampath D.
Published: February 2016

Design optimisation of a helicopter rotor blade is performed. The objective is to reduce helicopter vibration and constraints are put on frequencies and aeroelastic stability. The ply angles of the D-spar and skin of the composite rotor blade with NACA 0015 aerofoil section are considered as design variables. Polynomial response surfaces and space filling experimental designs are used to generate surrogate models of the objective function with respect to cross-section properties. The stacking sequence corresponding to the optimal cross-section is found using a real-coded genetic algorithm. Ply angle discretisation of 1°, 15°, 30° and 45° are used. The mean value of the objective function is used to find the optimal blade designs and the resulting designs are tested for variance. The optimal designs show a vibration reduction of 26% to 33% from the baseline design. A substantial reduction in vibration and an aeroelastically stable blade is obtained even after accounting for composite material uncertainty.
Aerodynamic and performance characteristics of a passive leading edge Kruger flap at low Reynolds numbers
Authors: Moraris V. M. , Lawson N. J. , Garry K. P.
Published: February 2016

An experimental and numerical study was performed on a Clark Y aerofoil with a 10% chord leading edge Kruger flap to examine its aerodynamic performance at Reynolds numbers of 0·6 × 106, 1 × 106, and 1·6 × 106, to help to identify the forces and moments acting on a basic configuration. A detailed comparison of the numerical and experimental data is presented in this paper. The leading edge flap was effective at high angles of attack with an increase in CL of up to 18% over a conventional no flap configuration and delayed separation by up to 3°. The moments around the Kruger flap rotation point were calculated from the numerical analysis as an initial stage in the design of a UAV passive flap system and they are also presented in the paper.
Investigation of skin porosity damping effects on free stream disturbance induced unsteady wing loads
Authors: Dahdi B. , Mamou M. , Khalid M. , Benissaad S. , Nemouchi Z.
Published: February 2016

Numerical simulations were performed to analyse the possibility of damping abrupt incoming free stream disturbances upon a porous aerofoil using an unsteady Reynolds-averaged Navier-Stokes (URANS) model. To mimic the turbulence disturbance levels that are typically encountered in the atmosphere, two flow configurations were considered. In the first configuration, the unsteadiness of the flow was created with vortices shed from a circular cylinder installed ahead of a WTEA-TE1 aerofoil. The continuous von Kármán shedding vortices contained within the cylinder wake were convected downstream and projected upon the aerofoil. In the second configuration, an instantaneous pair of discrete vortices was created by a rotational snapping of a flat plate, installed upstream of the aerofoil. Solid and porous aerofoil configurations, with porosity settings of 11 and 22%, were applied on 50% of the chord of the aerofoil starting from the leading edge. Both steady and unsteady flow simulations were performed to assess the performance of the porosity under steady and unsteady effects. The steady state flow simulations revealed a noticeable reduction in the aerofoil lift coefficient for the porous aerofoil. For unsteady solutions with a continuous or distinct series of vortices interacting with the aerofoil, the porosity showed insignificant damping of the lift coefficient amplitude. The porosity values investigated in the current exercise had indiscernible effect upon the unsteady lift-load alleviations caused by free stream disturbances.
A computational investigation of laminar shock/wave boundary layer interactions
Authors: Deepak N. R. , Gai S. L. , Neely A. J.
Published: February 2016

Hypersonic laminar flow past a compression corner has been numerically investigated using time-accurate computational fluid dynamics (CFD) approach. Two flow conditions were considered relevant to high and low enthalpy conditions with a total specific enthalpy of 19MJ/kg and 2·8MJ/kg. The Mach number and unit Reynolds number per metre were 7·5, 9·1 and 3·10 × 105 and 32·2 × 105 respectively. These free stream conditions provided attached, incipiently separated and fully separated flows for ramp angles between θw = 5° to 24°. A grid independence study has been carried out to estimate the sensitivity of heat flux and skin friction in the strong interaction regions of the flow. The investigation was carried out assuming the flow to be laminar throughout and high temperature effects such as thermal and chemical nonequilibrium are studied using Park’s two temperature model with finite rate chemistry. A critical comparison has been made with existing steady state computational and experimental data and the study has highlighted the importance of high temperature effects on the flow separation and reattachment.
A new method to reduce the noise of the miniaturised inertial sensors disposed in redundant linear configurations
Authors: Grigorie T. L. , Botez R. M.
Published: February 2016

This paper presents a new adaptive algorithm for the statistical filtering of miniaturised inertial sensor noise. The algorithm uses the minimum variance method to perform a best estimate calculation of the accelerations or angular speeds on each of the three axes of an Inertial Measurement Unit (IMU) by using the information from some accelerometers and gyros arrays placed along the IMU axes. Also, the proposed algorithm allows the reduction of both components of the sensors’ noise (long term and short term) by using redundant linear configurations for the sensors dispositions.

A numerical simulation is performed to illustrate how the algorithm works, using an accelerometer sensor model and a four-sensor array (unbiased and with different noise densities). Three cases of ideal input acceleration are considered: 1) a null signal; 2) a step signal with a no-null time step; and 3) a low frequency sinusoidal signal.

To experimentally validate the proposed algorithm, some bench tests are performed. In this way, two sensors configurations are used: 1) one accelerometers array with four miniaturised sensors (n = 4); and 2) one accelerometers array with nine miniaturised sensors (n = 9). Each of the two configurations are tested for three cases of input accelerations: 0ms−1, 9·80655m/s2 and 9·80655m/s2.
Enabling technologies for a centre-line tiltrotor
Authors: Burrage B.
Published: February 2016

The success of the MV-22 Osprey has created the opportunity for a new design of gunship, tailored to the task of escorting it, an opportunity identified by many. Existing and emerging rotorcraft technology does not appear to have the complete capability, so this centre-line tiltrotor approach is aimed specifically at the escort duty.

The mission is taken to be escorting the MV-22 throughout a land assault (Marine Corps), to provide cover while the MV-22 is on the ground at the landing zone, and to still have useful capacity for diversions. To meet this task this Escort concept stays with the same core physics of tilting rotors plus fixed wings of the Osprey, but re-configured for gunship duties. The rotors are removed from the wing tips to mount them on the aircraft centre-line as inter-meshing rotors tilting back one-at-a-time, to act as pusher props in the aeroplane mode. The merits and concerns of this approach are discussed.

The study first reviews present tiltrotor technology and how that may develop. It then reviews what may be achievable from the centre-line tiltrotor configuration, the targets needed in key design parameters and design sensitivities, defining what the enabling technologies must achieve for the Escort. In hover, key areas are rotor disk loading and figure of merit, and also the rotor blockage caused by the fuselage and wings. In winged flight, the proprotor propulsive efficiency and the aircraft lift-over-drag are key, and fundamental to the feasibility of any tiltrotor concept, there is the all important transition process.

At this conceptual stage of the Escort, the transition process stands out as the dominant risk, and one that touches on all the others, so it was decided to build and flight test a model. The flight test programme plans are described and initial flight results reported.
Fuel burn prediction algorithm for cruise, constant speed and level flight segments
Authors: Dancila B. D. , Botez R. , Labour D.
Published: February 2016

This paper presents a new algorithm that predicts the quantity of fuel burned by an aircraft flying at a constant speed and altitude. It considers the continuous fuel burn rate variation with time caused by the gross weight (and centre of gravity position) modification due to the fuel burn process itself. The algorithm was developed for use by the Flight Management System (FMS) and employs the same aircraft performance data as the existing FMS fuel burn prediction algorithms. The new fuel burn method was developed for aircraft models that use the centre of gravity position as well as for models that do not consider the centre of gravity position. This algorithm was developed for normal flight conditions. Algorithm performances were evaluated for two aircraft models: one for models that use an aircraft’s centre of gravity position – a more complex and computing intensive method, and one for those that do not use the centre of gravity position. The validation data were generated based on the information produced on a CMC Electronics – Esterline FMS platform that used identical aircraft models and performance data for identical flight conditions.
Aerodynamic design and experimental modelling of an innovative supersonic three-dimensional air-intake
Authors: Gounko Yu.P. , Mazhul I. I. , Kharitonov A. M.
Published: February 2016

Aerodynamic design of an innovative supersonic three-dimensional air-intake including a starting device has been carried out. The intake concept is based on the use of an external compression ramp in the form of a caret waverider. In a design flow regime, this ramp generates a plane oblique shock wave lying on its swept leading-edges and a subsequent two-dimensional isentropic compression wave. The intake starting is provided with a device special flaps of which in the throat are opened slightly in order to enlarge it and to form here both longitudinal and cross slots for air bleed and boundary-layer diversion. The same device can also serve for regulation of intake operating regimes depending on the flight velocity. The experimental model intake with a design Mach number MD = 2 has been developed and tested at flow Mach numbers 1·5, 1·75, and 2·0 in the T-313 supersonic wind tunnel based at ITAM. Flow patterns about the intake have been observed, and flow parameters characterising the intake performance have been measured. The experimental results obtained have confirmed the workability of the starting/regulating device; the data on the efficiency of the model intake have demonstrated its good characteristics in terms of the total pressure recovery.
Numerical simulation of ramp induced shock wave/boundary-layer interaction in turbulent flow
Authors: H. A. Asmelash , Martis R. R. , Singh A.
Published: February 2016

A computational study has been carried out to analyse the shock wave turbulent boundary layer interaction in a two-dimensional compression ramp flow for a free stream Mach number of 2·94. Ramp angles ranging from 8° to 24° are used to produce the full range of possible flow fields, including flows with minor separation, moderate separation, and significant amount of separation. The model has been analysed using 2D numerical simulations based on a commercially available Computational Fluid Dynamics (CFD) Code, Fluent, that employs k-ω Shear Stress Transport (SST) turbulence model. The computed data for surface pressure distribution indicated a good agreement with experiment. Numerical results obtained through the present series of computations indicate an increased extent of separated zone, and thus show increased upstream influence when compared to experiment. Total pressure loss has shown to increase downstream of separation location and increase when corner angle increases. Secondary separation has been observed for higher angles.
Probabilistic considerations for growth and detection of cracks from rivet holes in a lap joint
Authors: Cohen M. L. , Achenbach J. D.
Published: February 2016

In this paper, probabilistic considerations are introduced in a model for fatigue life prediction for a riveted lap joint using Paris’ law. Initial crack sizes are distributed according to a truncated lognormal distribution, which is chosen to avoid known complications due to Paris’ law. The stress intensity factor for a single rivet hole is calculated, and is generalized to a lap joint. The probability of the existence of a crack in two domains of interest are evaluated, and the effect of a single inspection, modeled using the Probability of Detection, is studied. Additionally, the probability of detection concept is extended by linking it to applied stress and number of elapsed cycles using Bayes’ theorem and ramifications are explored.
Aerothermodynamics of a hypersonic projectile with a double-disk aerospike
Authors: Yadav R. , Guven U.
Published: February 2016

The use of aerospikes at the nose of a hypersonic vehicle can substantially reduce its drag; however, the associated heat flux at the reattachment point is very high for turbulent flows. In this paper, the aerothermodynamics of a generic projectile model represented by a hemisphere- cylinder, fitted axisymmetrically with an aerospike at the nose is investigated numerically with a commercially available Navier Stokes Solver. The base model is a hemisphere-cylinder with a diameter of 40mm and an overall length of 70mm. An aerospike protrudes axisymmetrically at the nose of the base model and has a hemispherical cap from which another aerospike protrudes which again has a hemispherical cap, thus forming a double-disk aerospike. Compressible, axisymmetric Navier-Stokes Equations are solved for turbulent hypersonic flow of thermally perfect air with free stream conditions of Mach No 6·2 at standard sea level atmospheric conditions. The results for the model with double-disk aerospikes are compared with those of hemisphere-cylinder without aerospike. The results suggest that the use of double-disk aerospike can favourably reduce the turbulent reattachment heat flux along with suitable drag reduction of the main body.
Stalling transport aircraft
Authors: Bolds-Moorehead P. J. , Chaney V. G. , Lutz T. , Vaux S.
Published: February 2016

Airbus and Boeing are cooperatively presenting this topic dealing with transport aircraft stalls. The paper will begin by defining a stall, followed by a review of requirements, predictive validation and flight testing. There are various ways of designing modern jet transports for the stall regime such as aerodynamic approaches, flight deck indications, and augmentation control laws to deal with the high angle-of-attack (α) arena. The goal of augmented control laws for high α is common – no full aerodynamic stall or loss of climb performance should occur in the operational flight envelope, in Normal flight control modes. The validation techniques employed in preparation for a flight test campaign will follow. These include flight characteristic predictions based on wind-tunnel data as well as pilot-in-the-loop simulation rehearsals. The preparation for flight testing will be reviewed from both the engineer and pilot viewpoints. This will be followed by a review of various flight testing that has been conducted. The paper will close with a brief foray into what the future of transport stalls could be – perhaps protection features in degraded flight control modes? What are the benefits as well as drawbacks to increased augmentation for high α?
Spin induced aerodynamic flow conditions on full-scale aeroplane wing and horizontal tail surfaces
Authors: Hoff R. I. , Gratton G. B.
Published: February 2016

The aerodynamic flow conditions on wings and tail surfaces due to the rotational motion of a spinning aeroplane have been investigated in a full-scale spin flight research programme at the Brunel Flight Safety Laboratory. The wing upper surface vortex has been visualised using smoke and tufts on the wing of a Slingsby Firefly. The flow structures on top of both wings, and on top of the horizontal tail surfaces, have also been studied on a Saab Safir. The development of these rotational flow effects has been related to the spin motion and the effect on the spin dynamics has been studied and discussed. Evidence suggests that the turbulent wake from the wing upper surface vortex impinges the tail of the aircraft during the spin entry. It is hypothesised that the turbulent flow structure on the outside upper wing surface is due to additional accelerations induced by the rotational motion of the aeroplane. Furthermore, the lightening in stick force during spin entry and the apparent increase in push force required for spin recovery corresponds to the observed change in flow condition on the horizontal tail. The difference in pressure on the upper and lower horizontal tail surfaces have been measured using differential pressure sensors, and the result corresponds both with the observed flow conditions and earlier research results from NASA.
Fuel burn and emissions evaluation for a missed approach procedure performed by a B737-400
Authors: Dancila R. , Botez R. , Ford S.
Published: February 2016

This paper presents the results of a study conducted at the Laboratoire de recherche en commande active, avionique et aéroservoélasticité, École de technologie supérieure, regarding the costs in fuel burn and pollutant emissions corresponding to a flight profile determined by a missed approach procedure. The evaluated missed approach flight profile starts at the point where the missed approach decision is made and ends at the same point, after the aircraft completes the missed approach procedure.

This study uses the fuel burn and pollutant emissions data for a Boeing 737-400 aircraft (chosen at random for this study), published by the European Environment Agency, and the standard flying cycle model elaborated by Group 08 of the Task Force on Emissions Inventories and Projections – a task force created by the United Nations Economic Commission for Europe (UN ECE)/the co-operative program for the monitoring and evaluation of the long-range transmission of air pollutants in the Europe (EMEP). The missed approach fight profile is based on the Area Navigation/Required Navigation Performance procedure for runway 13R of the King County International Airport/Boeing Field (BFI) in Seattle.

Four study cases are considered for the missed approach flight evaluation. These cases correspond to four navigation profiles – a combination of two lateral navigation profiles, one with a 20 nautical miles holding pattern and the other without, and two vertical navigation profiles. The results obtained for the missed approach flight profiles, in terms of fuel burn and emissions, are compared with the fuel burn and emissions reference data corresponding to a standard approach procedure and complete flights (from taxi out to taxi in).
Repetitively enhanced neural networks method for complex engineering design optimisation problems
Authors: Van Nguyen N. , Lee J-W. , Tyan M. , Kim S.
Published: February 2016

A Repetitively Enhanced Neural Networks (RENN) method is developed and presented for complex and implicit engineering design problems. The enhanced neural networks module constructs an accurate surrogate model and avoids over-fitting during neural networks training from supervised learning data. The optimiser is executed by the enhanced neural networks models to seek a tentative optimum point. It is repetitively added into the supervised learning data set to refine the surfaces until the RENN tolerance is reached. The RENN method demonstrates the effectiveness and feasibility for a 2D highly non-linear numerical example and the structure design of a two-member frame reaching a convergent solution at 10 and 15 iterations at the maximum error of 1% when compared with the exact solution. Then, the RENN method is applied for a long endurance unmanned aerial vehicle (UAV) aerofoil design optimisation. A Class/Shape function transformation (CST) geometry parameterisation method represents an accurate UAV aerofoil with ten geometry design variables. The high-fidelity analysis solver with structured mesh is used for a UAV aerofoil design problem. Using the RENN method, an optimal UAV aerofoil is obtained using 88 high fidelity evaluations at an error of 1·24%. The process reduces the computational time by 81·2% compared with the full high fidelity model. The optimal aerofoil shows a drag reduction of 10·8% in the cruise condition and an improvement in the maximum lift coefficient and stall angle-of-attack when compared with the baseline AG24 aerofoil.
Control of separation in the concave portion of contraction to improve the flow quality
Authors: Ghorbanian K. , Soltani M. R. , Manshadi M. D. , Mirzaei M.
Published: February 2016

Subsonic wind tunnel experiments were conducted to study the effect of forced transition on the pressure distribution in the concave portion of contraction. Further more, the effect of early transition on the turbulence level in the test section of the wind tunnel is studied. Measurements were performed by installing several trip strips at two different positions in the concave portion of the contraction. The results show that installation of the trip strips, have significant effects on both turbulence intensity and on the pressure distribution. The reduction in the free stream turbulence as well as the wall static pressure distribution varied significantly with the location of the trip strip. The results confirm the significant impact of the tripped boundary layer on the control of adverse pressure gradient. The trip strip at X/L = 0.115 improves pressure distribution in contraction and reduces turbulence intensity in the test section, considerably.
Key aerodynamic technologies for aircraft engine nacelles
Authors: Raghunathan S. , Benard E. , Watterson J. K. , Cooper R. K. , Curran R. , Price M. , Yao H. , Devine R. , Crawford B. , Riordan D. , Linton A. , Richardson J. , Tweedie J.
Published: February 2016

Customer requirements and vision in aerospace dictate that the next generation of civil transport aircraft should have a strong emphasis on increased safety, reduced environmental impact and reduced cost without sacrificing performance. In this context, the School of Mechanical and Aerospace Engineering at the Queen’s University of Belfast and Bombardier have, in recent years, been conducting research into some of the key aerodynamic technologies for the next generation of aircraft engine nacelles. Investigations have been performed into anti-icing technology, efficient thrust reversal, engine fire zone safety, life cycle cost and integration of the foregoing with other considerations in engine and aircraft design. A unique correlation for heat transfer in an anti-icing system has been developed. The effect of normal vibration on heat transfer in such systems has been found to be negligible. It has been shown that carefully designed natural blockage thrust reversers without a cascade can reduce aircraft weight with only a small sacrifice in the reversed thrust. A good understanding of the pressure relief doors and techniques to improve the performance of such doors have been developed. Trade off studies between aerodynamics, manufacturing and assembly of engine nacelles have shown the potential for a significant reduction in life cycle cost.
Transoral robotic resection of a large schwannoma in the retropharyngeal space
Authors: Gungadeen A , Lisseter R , Manickavasagam J , Paleri V
Published: February 2016

Background:

External approaches have been traditionally used for the complete excision of large retropharyngeal space lesions.

Case report:

This paper describes a case of a large schwannoma of the retropharyngeal space excised transorally with the use of a robotic system. This lesion measured 2.7 × 1.2 cm in axial dimensions and over 5.8 cm in craniocaudal length. The lesion was delivered en bloc with an intact capsule. No peri- or post-operative complications were encountered. The procedure allowed quick resumption of an oral diet and a return to normal activity for the patient.

Conclusion:

This is, to our knowledge, the first report of this technique used in the excision of a large retropharyngeal space mass.
The paradoxical psychological effects of lysergic acid diethylamide (LSD)
Authors: Carhart-Harris R. L. , Kaelen M. , Bolstridge M. , Williams T. M. , Williams L. T. , Underwood R. , Feilding A. , Nutt D. J.
Published: February 2016

Background

Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or psychedelic that modulates consciousness in a marked and novel way. This study sought to examine the acute and mid-term psychological effects of LSD in a controlled study.

Method

A total of 20 healthy volunteers participated in this within-subjects study. Participants received LSD (75µg, intravenously) on one occasion and placebo (saline, intravenously) on another, in a balanced order, with at least 2 weeks separating sessions. Acute subjective effects were measured using the Altered States of Consciousness questionnaire and the Psychotomimetic States Inventory (PSI). A measure of optimism (the Revised Life Orientation Test), the Revised NEO Personality Inventory, and the Peter's Delusions Inventory were issued at baseline and 2 weeks after each session.

Results

LSD produced robust psychological effects; including heightened mood but also high scores on the PSI, an index of psychosis-like symptoms. Increased optimism and trait openness were observed 2 weeks after LSD (and not placebo) and there were no changes in delusional thinking.

Conclusions

The present findings reinforce the view that psychedelics elicit psychosis-like symptoms acutely yet improve psychological wellbeing in the mid to long term. It is proposed that acute alterations in mood are secondary to a more fundamental modulation in the quality of cognition, and that increased cognitive flexibility subsequent to serotonin 2A receptor (5-HT2AR) stimulation promotes emotional lability during intoxication and leaves a residue of ‘loosened cognition’ in the mid to long term that is conducive to improved psychological wellbeing.
Lost and unfulfilled relationships behind emotional loneliness in old age
Authors: TIILIKAINEN ELISA , SEPPÄNEN MARJAANA
Published: February 2016

Using a qualitative approach, this article examines how the experiences of emotional loneliness are embedded in the everyday lives and relationships of older adults. Ten in-depth interviews were conducted in 2010 with older people who reported feeling lonely, often or all the time, during a cohort study in southern Finland. The research reveals the multifaceted nature of loneliness and its causes. Behind emotional loneliness, we identified lost and unfulfilled relationships, involving the loss or lack of a partner, the absence of a meaningful friendship, complex parenthood and troubling childhood experiences. Most of the interviewees have faced loneliness that only began in old age, but for some, loneliness has been present for nearly a lifetime.
Religious and Legal Pluralism in Recent African Constitutional Reform
Authors: Green M. Christian
Published: February 2016

Something unexpected has been happening in Africa—and not just Northern Africa, the locus of democratic revolutions since January 2011, when a winter's discontent produced an early Arab Spring. Over the last several years, several sub-Saharan African nations have held democratic elections, produced new constitutions, and even partitioned themselves in relative peace, despite the often dire predictions of foreign governments, media, and election-monitoring organizations.

In many cases, the constitution and reconstitution of these states has been accomplished by means of the referendum vote—sometimes viewed as the anti-democratic purview of special interests in the developed West, but having greater respect and utility as a tool of democracy in the developing South. Kenya produced a new constitution in 2010 by a referendum that has been lauded by international observers for its peaceful process and outcome. The Kenyan referendum followed general elections in 2007, whose results were marred by violence in early 2008. The nearby countries of Zambia and Tanzania are currently in the process of constitutional reform, drawing lessons from Kenya's unexpectedly harmonious proceedings. In all three countries, the constitutional review processes have raised, among other issues, questions of legal pluralism, religious freedom, and relations between the Christian majority and Muslim minority.
Evolving Views of Islamic Law in Turkey
Authors: Powell Russell
Published: February 2016

The tradition of Kemalist secularism (laiklik) in Turkey is often cited to distinguish Turkey as an exceptional case among predominantly Muslim countries. While it is true that the Turkish Constitution, laws, and legal opinions approach the relationship between the state and religion very differently than those of Iran, Saudi Arabia, Egypt, or even Indonesia, it would be wrong to underestimate the role that religion plays in the formation of Turkish legal norms, including citizen understanding of those norms. There is a wealth of literature describing the nature of Turkish secularism and its evolution. A number of both quantitative and qualitative studies inquire about the preference forShari'aamong Turkish voters. The typical question asks whether respondents favor the establishment of aShari'astate. Over the past fifteen years, these surveys have received response rates ranging between five and twenty-five percent in favor of such a state. However, these results are extremely problematic, because they do not provide any context or meaning for “the establishment of aShari'astate,” either for those who favor it or for those who oppose it. This study begins to unpack the range of possible meanings attributed toShari'awithin Turkey, both among voters and among intellectuals, as a framework for future empirical studies and as a basis for deeper understandings of the role of Islam within Turkish law and politics.
A Science Like Any Other? Classical Legal Formalism in theHalakhicJurisprudence of Rabbis Isaac Jacob Reines and Moses Avigdor Amiel
Authors: Lindell Yosef
Published: February 2016

Nineteenth century jurists sought to make law a science like any other. They believed that the law was not an unprincipled mass of archaic and contradictory rules, nor an extinct body of Latin words that should be venerated in a church reliquary and seldom studied. Rather, they said that it was time for law to take its place in the university and to be dissected under the microscope of scientific analysis. It was by these methods that law's fundamental axioms would be uncovered—which would in turn explain the relationship of all its parts to the whole. And with the right set of principles, new data could be effortlessly incorporated into an ever-growing scientific taxonomy of the law.

This mode of thinking dominated both European and American legal jurisprudence in the mid- to late-nineteenth century and the early twentieth century, although it went by different names. One fundamental thread ran throughout—the law was not unprincipled, but logical. It could be reasonably explained and rationally ordered. This paper demonstrates that Rabbis Isaac Jacob Reines and Moses Avigdor Amiel, two important Jewish thinkers living at the turn of the twentieth century, saw Jewish law, orhalakha, in the same light. Although Reines and Amiel may not have been directly influenced by secular jurisprudence, many of the elements of this classical legal science provide an interesting parallel to the answers these two thinkers gave to some of the oldest problems of Jewish law. Most notably, the way in which Reines and Amiel explained the connection between the Torah's oral and written components, as well as the way in which they asserted the internal coherence ofhalakhicjurisprudence, was similar to the legal formalism of their contemporaries.
Common Cause in the Culture Wars?
Authors: Reyes René
Published: February 2016

A significant body of legal academic writing produced in recent years has argued that one of the primary purposes of the First Amendment's Religion Clauses was to protect freedom of conscience. But in the two decades since the Supreme Court's decision in Employment Division v. Smith, a number of commentators have suggested that freedom of conscience has lost its place as the focus of Free Exercise and Establishment Clause jurisprudence. Indeed, some have gone so far as to argue that protection for freedom of conscience has disappeared from the Free Exercise Clause almost entirely, leaving conduct that is motivated by a religious conscience without special constitutional protection. To be sure, some protection for freedom of conscience remains—but its constitutional source is often to be found outside of the Religion Clauses and its concern is often with non-religious activity.

This evolution of doctrine has been extensively criticized by scholars of the Religion Clauses, many of whom view these developments as departures from original intent and from long-settled constitutional practice. Michael McConnell, Martha Nussbaum, and others have also advanced normative critiques, arguing that religious conscience is in many ways distinctive and merits distinctive constitutional solicitude under the Free Exercise Clause. At the same time, the Supreme Court's rejection of special privileges for religious claims of conscience has been welcomed by other scholars, some of whom have argued that preferential protection for religiously-motivated conduct is a form of unconstitutional discrimination. Two of the most prominent proponents of this position are Christopher Eisgruber and Lawrence Sager, who maintain that the Religion Clauses should be read to promote equal liberty rather than to provide special exemptions.
“For the Judgment is God's”: Human Judgment and Divine Justice in The Hebrew Bible and in Jewish Tradition
Authors: Shapira Haim
Published: February 2016

One of the most striking images of God, both in the Bible and in Jewish tradition generally, is that of judge: “The judge of all the earth.” In this sense, one may describe God as He who holds in His hands all legal authority: He is the legislator, He is the judge, and He is the one who executes judgment. Alongside God's judgment, the Bible recognizes the existence of a human system of judgment, in which human beings act as judges; indeed, it even commands it: “You shall appoint judges and officers in all your gates.” What is the relation between God, the judge of all the earth, and those human beings who fulfill the function of judges? The majority of classical Jewish sources in the Bible and in Rabbinic literature that deal with law and the legal system reflect a certain relationship between human judgment and divine justice. Thus, we find in the Bible the notion that God emanates His authority to the judges who perform this function. In this spirit, Moses commands the judges whom he has appointed: “judge righteously… for the judgment is God's.” The relation assumed here between God and human judgment finds expression in different ways, extending over a considerable spectrum. At one end, one might describe God as the transcendent source of authority of the legal system, whose practical significance is limited. On the other end, one might describe it as a Divine Presence that inspires the judges and even allows them to appeal to God and to involve Him in the legal decision.
“Command and Coercion”: Clerical Immunity, Scandal, and the Sex Abuse Crisis in the Roman Catholic Church
Authors: Wirenius John F.
Published: February 2016

On December 29, 1170, in the late afternoon (and thus after the main meal of the day but shortly before vespers), four knights entered Canterbury Cathedral. Impelled, as far as history knows, by the angry words of King Henry II, “will no one rid me of this turbulent priest,” they had come to confront Archbishop Thomas Becket and win King Henry's favor by forcing the long-simmering dispute between Becket and his king to some final resolution. When the Archbishop refused their conflicting demands and reacted with scorn to their insults, the knights withdrew, only to arm themselves and follow Becket into the cathedral. As the traditional account has it:

[t]he bell for vespers began to sound, and the archbishop, with his cross borne in front of him, made his way in as usual into the cathedral. Hardly had he reached the ascent to the choir than the noise of armed men and the shout of the knights announced that the pursuers were at hand. “Where is the archbishop, where is the traitor?” resounded through the hollow aisles, mingling strangely with the recitation of the psalms in the choir. Becket, hearing this, turned back a few steps, and calmly awaited their approach in the corner of the northern transept before the little altar of S[t .] Benedict. “Here,” he cried, “is the archbishop—no traitor, but a priest of God.” Awed by his demeanor, and perhaps by the sanctity of the place, no one dared strike. A parley began. They sought to lash their failing courage into action by words. A hasty and insulting epithet gave Fitz Urse the opportunity he wanted. A blow aimed at the archbishop's head only knocked his skull-cap to the ground, but it was enough to loose the bandogs of hell. A stroke from Tracy cut off the tonsured back of [Becket's] skull, another from Brito brought him to his knees.