Scale Prototype Research Articles

Three-dimensional simulation effects of trailing-edge actuation on a morphing A320 wing by means of hybrid turbulence modelling

PurposeThis study aims to investigate the effects of electroactive morphing on the Airbus A320 Reduced Scale prototype of the H2020 N° 723402 European Research project smart morphing and sensing (SMS) for aeronautical configurations [1],[2].Design/methodology/approachThe flow regimes correspond to low subsonic take-off conditions. The morphing is applied through the vibration and slight deformation of the near trailing edge region; respecting the way, this actuation has been applied on the experimental prototype using micro fibre composite actuators. Optimal frequency range has been used, associated with low amplitudes of deformation with the Arbitrary Lagrangian Eulerian methodology. This study used an adapted turbulence modelling with the organised eddy simulation (OES) as well as a hybrid approach delayed detached eddy simulation – with embedded OES (DDES–OES), able to sensitise and keep up the coherent structures development.FindingsThe morphing at an optimal frequency (300 Hz) and amplitude (0.7 mm), applied on a length (3.5 cm) near the trailing edge, has been studied at Reynolds number 1 million and incidence of 10°. The effects on the main flow instabilities and on the turbulent vortex structures are analysed using proper orthogonal decomposition. A modification of the wake structures and a formation of organised rows of vortices along the shear layer are obtained. This leads to a quasi-two-dimensional wake, benefits on the aerodynamic performance and a decrease of the frequency peaks in the spectrum, corresponding to an attenuation of the coherent structures.Originality/valueThis study provides a fundamental understanding of how the actuation modifies the coherent and turbulent vortex structures around the wing and in the wake.

Growth comparison of Arthrospira platensis in different vessels: standard cylinder vs. enhanced surface area at low light

ABSTRACT A laboratory scale prototype of a novel tube called AlgaTube™ (patent pending) was evaluated for growth of Arthrospira platensis (commonly referred to as Spirulina) in a controlled, 10-day batch trial at low light intensity. The two cultures (control and prototype) were grown in identical conditions inside a closed incubator space at 32°C with a mean light intensity of 55 µmol photons m−2 s−1 LED light, consisting mostly of red and blue wavelengths with some full spectrum background radiation. OD590 was measured daily and converted to Concentration (Cd, g l−1) using a standard curve. Four independent replicates of the trial were run. Six biomass growth metrics were evaluated and compared. Across the board, all six growth metrics showed higher rates of biomass growth in the AlgaTube™. Maximum concentration was 34% higher (p = 0.02), cumulative production was 41% higher (p = 0.02), specific growth rate was 17% higher (p = 0.02), maximum specific growth rate was 23% higher (p = 0.02), mean daily production was 41% higher (p = 0.001), and maximum daily production was 38% higher (p = 0.19). We conclude that the novel shape of the AlgaTube™ prototype increased biomass growth rates. We believe that this study constitutes successful proof-of-concept for the AlgaTube™, but further studies are needed to optimize its performance.

Neurofuzzy Data Aggregation in a Multisensory System for Self-Driving Car Steering

In the self-driving vehicles domain, steering control is a process that transforms information obtained from sensors into commands that steer the vehicle on the road and avoid obstacles. Although a greater number of sensors improves perception and increases control precision, it also increases the computational cost and the number of processes. To reduce the cost and allow data fusion and vehicle control as a single process, this research proposes a data fusion approach by formulating a neurofuzzy aggregation deep learning layer; this approach integrates aggregation using fuzzy measures μ as fuzzy synaptic weights, hidden state using the Choquet fuzzy integral, and a fuzzy backpropagation algorithm, creating a data processing from different sources. In addition, implementing a previous approach, a self-driving neural model is proposed based on the aggregation of a steering control model and another for obstacle detection. This was tested in an ROS simulation environment and in a scale prototype. Experimentation showed that the proposed approach generates an average autonomy of 95% and improves driving smoothness by 9% compared to other state-of-the-art methods.

Analysis of transient seepage through a river embankment by means of centrifuge modelling

Earthen river embankments are typically in unsaturated conditions during their lifetime and the degree of saturation within their bodies may vary significantly throughout the year, due to seasonalfluctuations of the river stage, as well as infiltrations of meteoric precipitation and evapotranspiration phenomena. Given the significant effects of partial saturation on the hydro-mechanical behaviour of soils, realistic assumptions on the actual water content distribution inside the embankments are essential forproperly modelling their response to hydraulic loadings. In this framework, centrifuge modelling is a useful tool to get insights into the evolution of saturation conditions of a water retaining structure during flood events. It allows for the direct observation of the groundwater flow process, which is hardly detectable at the prototype scale, enabling, at the same time, the validation and calibration of predictive numerical tools.In this paper, the results of a centrifuge test carried out on small-scale physical model of a compacted silty clayey sand embankment subjected to a simulated high-water event, at the enhanced gravity of 50-g, are presented and discussed. The physical model was carefully instrumented with potentiometers, miniaturized pore pressure transducers and tensiometers. Pore pressures and suctions measured during the experiment showed that the stationary flow conditions were reached only after an unrealistic hydrometric peak persistence. It therefore emerges that, for the design and/or the assessment of the safety conditions of a river embankment similar to the one tested, the simplified hypothesis of a steady-state seepage, in equilibrium with the maximum river stage expected could result, in many cases, an excessively conservative assumption.

Scaling Effect On Inter-Turn Short-Circuit Fault of PM Machines for Wind Power Application

This paper proposes a general analytical model of surface-mounted permanent magnet (SPM) machines with series-connected coils under inter-turn short circuit (ITSC) fault. One prominent feature of this fault model is that the air-gap and slot-leakage components of inductances under fault are calculated separately, and the influences of pole number and spatial distribution of coils have been considered in the calculations. In the model, the winding function approach (WFA) is used to calculate the air-gap inductance components by considering all space harmonics whilst slot-leakage inductance components are obtained by using slot permeance method. The proposed fault model built in Matlab/Simulink is validated by time stepping FE simulations for a 3 kW 96-slot 32-pole SPM machine. The fault model has acceptable accuracy and is suitable for the fast evaluation of fault performance of SPM machines and its accuracy considering core saturation can be improved using FE-based results. Other power ratings (0.5 MW and 3 MW) have also been investigated to study the scaling effect on machine fault-tolerant capability. A 12-slot 4-pole small scale prototype has been built to validate the developed fault models.

Large-scale experiments on tsunami inundation and overtopping forces at vertical sea walls

Tsunami are very long gravity waves that may cause significant damage to coastal sea walls. The majority of relevant design codes and research papers that describe methods for predicting tsunami loads on coastal walls consider the scenario of transitory force from a bore-led wave. This does not relate to tsunami that do not form bore waves. Bore fronts generally cause short term spikes in force, which may have little effect on the vulnerability of massive structures. Post disaster accounts suggest that most coastal walls show damage that implies failure modes that occur over moderate to long durations. Therefore it is likely that the bore front assumption gives an overly conservative prediction of maximum force, and may not capture the full timescale of tsunami loading. This paper uses a pneumatic tsunami generation facility to determine the force loading on two vertical coastal sea walls during tsunami inundation. Two sea-wall models, 0.15 and 0.25 m high, with crown widths of 0.1 m (7.5 and 12.5 m at a nominal prototype scale of 1:50) are tested. It is shown that bore fronts only occur for short period waves over the bathymetry tested. Bore fronts cause a very short period spike in force, which is followed by a transitory force approximated by the hydrostatic pressure equation. The loading of tsunami length waves of periods ≥ 40 s (280 s prototype at 1:50 scale), which do not break is not greater than 1.2 times the hydrostatic force. Overtopping volume is positively correlated to the time duration of positive upstream head over the crest, rather than its maximum value. Overtopping causes a small increase in the horizontal load due to the addition of a drag and momentum load. The magnitude and time of these effects are small and short-lived in comparison to the hydrostatic load. The results compare well with available equations based on hydrostatic force and the engineer may apply a desired multiplying coefficient of a factor of at least 1.2 to account for any added pressure and momentum, and the factor of safety intended. • Tsunami loads on vertical walls are no greater than 1.2 times the theoretical hydrostatic load. • Only shorter wave periods break and form bores; longer tsunami-length waves do not break. • Tsunami overtopping volume is related to the duration of positive head over the crest. • Tsunami overtopping applies a relatively small (against the hydrostatic load) additional horizontal force.

Partial discharges detection in 1 MV power supplies in MITICA experiment, the ITER heating neutral beam injector prototype

MITICA (Megavolt ITER Injector & Concept Advancement), the full scale prototype of ITER Heating Neutral Beam, is under realization at the Neutral Beam Test Facility (Padova, Italy). It is designed to deliver 16.5 MW to ITER plasma, obtained by accelerating negative Deuterium ions up to 1 MeV for a total ion current of 40 A and then neutralized.MITICA Acceleration Power Supply is composed of several non-standard equipment, beyond industrial standard for insulation voltage level (-1 MVdc) and dimensions.Voltage withstand tests (up to 1.265 MVdc) have been performed in five subsequent steps (from 2018 to 2019), according to the installation progress, after connecting equipment belonging to different procurements.During integrated commissioning, started in 2021, two breakdowns occurred in a position of the HV plant not still identified, so they could be occurred either in air or in SF6. To identify the locations of possible weak insulation points, the existing diagnostics for partial discharge detection (the precursor of breakdowns) as a first step have been improved on air-insulated parts by consisting in a set of instrumentation, like capacitive probes and off-the-shelf instruments for AC application (acoustic and electromagnetic sensors).The paper deals with the instruments qualification to assess their suitability for DC usage and then with the investigation performed in MITICA, in particular:1) sensitivity assessment campaign, with artificially produced corona effect to identify the minimum threshold of each diagnostics2) voltage application to MITICA plant, moving the instrumentation around equipment and increasing progressively the voltage looking for corona phenomena to identify possible weak insulation points.

ECOPOOL+++: Developing a sustainable outdoor heated swimming pool

The University of Algarve, in consortium with “Cristal Construções – Materiais e Obras de Construção Civil”, “Itelmatis Control Systems” and “Itecons – Instituto de Investigação e Desenvolvimento Tecnológico para a Construção, Energia, Ambiente e Sustentabilidade”, is developing a new concept of outdoor heated sustainable swimming pool, having a higher energy efficiency and lower environmental footprint. The main objective is to minimise energy and water consumptions, while assuring a comfortable temperature for the user, extending the utilization of the pool in the Algarve region, from the summer months, to at least 8 months of the year. In order to do it, different systems will be tested, including solar thermal and photovoltaic panels, inverted underfloor heating, heat accumulator exchanger with phase change materials and energy dissipating pipes. An innovative thermal insulation system will be included in the interior of the pool tank, together with a new system for the covering of the water plane. All these systems will be monitored and controlled by an industrial automation system that will communicate, via a programmable logic controller, using industry standard communication protocols, with a SMART platform, that will be in charge of the global operation's optimisation. This platform will support an intelligent and predictive control and monitoring module, that controls the automation system to maximize the energy usage of the renewable sources, while assuring the user preferences. One of the main outputs of this project is the construction of a smaller scale prototype of a swimming pool, with the characteristics mentioned above, in order to test and validate the proposed developments.

TelePix – A fast region of interest trigger and timing layer for the EUDET Telescopes

Test beam facilities are essential to study the response of novel detectors to particles. At the DESY II Test Beam facility, users can test their detectors with an electron beam with a momentum from 1–6 GeV. To track the beam particles, EUDET-style telescopes are provided in each beam area. They provide excellent spatial resolution, but the time resolution is limited by the rolling shutter architecture to a precision of approximately 230 μs. Since the demand on particle rates – and hence track multiplicities – is increasing timing is becoming more relevant. DESY foresees several upgrades of the telescopes. TelePix is an upgrade project to provide track timestamping with a precision of better than 5 ns and a configurable region of interest to trigger the telescope readout. Small scale prototypes have been characterized in laboratory and test beam measurements. Laboratory tests with an injection corresponding to 2300 electrons show a S/N of above 20. Test beam characterization shows efficiencies of above 99% over a threshold range of more than 100 mV and time resolutions of 2.4 ns at low noise rates.

Enhancing Grid Integration and Design of Low Speed PMSGs by Exploiting SRF-PLL-Based Sensorless Control and Holistic Modeling

This article proposes a holistic co-design framework with a low-cost approach for a permanent magnet synchronous generator (PMSG) that enables to optimizes both the electromagnetic and mechanical design, in conjunction with the injection of the maximum available power towards the power grid through a controlled electronic back-to-back converter. The proposed sensorless controller includes a hybrid PLL with a dynamically adjustable tabulated gains system and a feedforward frequency estimator. These add-ons allow to precisely track the speed and angle of the rotor shaft for near-zero speeds. This methodology includes the development of analytical models for the structural, magnetic and electrical components. The efficiency and performance of the machine and controller is verified by simulation under different load conditions and high angular speed variability of a 1.5 kW scale prototype in JMAG and Matlab & Simulink™ environments, reaching an efficiency of 80%.

Carbon fiber reinforced polymer and tensegrity structures in search of model architectural and engineering solutions

The current era of nanomaterials brings advancements in science and technology. This creates new solutions and possibili-ties in the creation of novel spatial structures. This study leads through the presentation of iconic architectural objects creat-ed with the use of high strength composite materials and tensegrity structure. Then presents the design process, numerical simulations of the three-way tensegrity grid prototype module. Static stress simulations were done within the simulation engine of the Fusion 360 software. Moreover, 1:1 scale prototype was developed. It could be used as a modular construction slab of a novel architectural design. One of the key characteristic features of high strength composite materials, high strength-to-weight ratio, combined with tensegrity structures allows to develop lightweight and hence very durable spatial structures. This gives tensegrity structures a very low dead load value as compared to traditional reinforced concrete struc-tures. Thanks to the application of high strength and hence lightweight materials, the dead load of the prototype is only 0,18 kN/m2.

Three-dimensional Analytical Modeling of Axial Flux Permanent Magnets Maglev Motor

The three-dimensional(3D) analytical model of the magnetic field in an Axial Flux Permanent Magnets Maglev Motor(AFPMMM) is proposed and investigated the influence of the structural parameters on electromagnetic characteristics. Firstly, the topology and working principle of the AFPMMM is introduced, and the model is transferred into a mathematical model in 3D cartesian coordinate. Then, the volume integral method and equivalent current sheets model is applied to find the 3D magnetic field distribution function of Halbach rotor. A unified form expression can be obtained by two dimensional discrete fourier transform (2-D DFT) is applied on the 3D magnetic field distribution function. Thirdly, the conductive and nonconductive regions of AFPMMM will be formulated by the second order vector potential (SOVP) to built the 3D analytic model. The expression of the lift force, torque and power losses was derived. Besides, the relationship between electromagnetic characteristics and structural parameters of the AFPMMM were analyzed based on 3D analytic model and validated using the 3D finite element analysis(FEA). Finally, the experiments based on a small scale prototype are carried out to verify the analytical results.

Evaluation of a Hydrogen Powered Scooter Toy Prototype

Electric scooters are used as alternative ways of transport because they easily make travel faster. However, the batteries can take around 5 h to charge and have an autonomy of 30 km. With the presence of the hydrogen cell, a hybrid system reduces the charging times and increases the autonomy of the vehicle by using two types of fuel. An increase of up to 80% in maximum distance and of 34% in operating times is obtained with a 1:10 scale prototype with the hydrogen cell; although more energy is withdrawn, the combined fuel efficiency increases, too. This suggests the cell that is used has the same behavior as some official reported vehicles, which have a long range but low power. This allows concluding that use of the cell is functional for load tests and that the comparison factor obtained works as input for real-scale scooter prototypes to compete with the traditional electric scooters.

Reconfigured Photovoltaic Model to Facilitate Maximum Power Point Tracking for Micro and Nano-Grid Systems

PV systems are a popular energy resource, prevalent worldwide; however, shade faults manifested in PV systems limit its power conversion efficiency. The occurrence of multiple power peaks and their location are highly uncertain in PV systems; this necessitates the use of complex maximum power point tracking algorithms to introduce high voltage oscillations. To address this issue, a new reconfigurable PV array to produce a global maximum power point (GMPP) algorithm close to the Voc regions was introduced. This enables the use of a simple Perturb and Observe (P&O) algorithm to easily track GMPP. For reconfiguration, a simple 5 × 5 PV array is considered, and a new physical relocation procedure based on the position square method is proposed. Performance of the proposed reconfiguration model is tested for four various shade events and its row current evaluations are comprehensively analyzed. Furthermore, evaluations of fill factor, mismatch loss, and power loss are quantitatively compared against Dominance Square and TCT schemes. Since the power enhancement is ensured in a reconfigurable PV array, the fixed reconfiguration is tailored to suit residential PV and microgrid systems. For MPP evaluations, hardware demonstrations are performed with a lab scale prototype model developed with a PV simulator and a DC–DC power electronic interface. The I–V characteristics of conventional and reconfigured models are programmed into the simulator and the use of the hill climbing algorithm is validated. To analyze the voltage and power oscillations with MPP tracking, the PSO algorithm is also tested for two test patterns and its results are comprehensively studied.

Experimental study on dynamic characteristics of a monopile foundation based on local scour in combined waves and current

Scour is one of the key factors causing the collapse of buildings (structures) in water. Pile foundations are often subject to the combined actions of waves and current, resulting in weakened soil overturning resistance and changes in natural vibration frequency, which may lead to vortex-induced vibration under the action of fluid flow and cause fatigue damage. A series of experiments under current-only, wave-only, and combined wave-current conditions were carried out in a wave-current flume to investigate the scour phenomenon around a monopile and the change in natural vibration frequency of the monopile foundation along the flow and vertical directions caused by local scour. The scour depth under combined wave-current conditions is greater than that under current-only conditions, and increases accordingly with the increase of the flow velocity and the decrease of the water depth. Furthermore, the scour phenomenon under different flow patterns was analyzed according to the variation of pulsation pressure. The empirical formula for the natural vibration frequency of the monopile foundation considering the local scour under current-only and combined wave-current conditions was established respectively. Compared with the experimental results, the maximum error is 10%, indicating that the empirical formula has a high degree of confidence. The above empirical formula obtained from the indoor scale model is applied to the field test, and the maximum relative error is 14.37%, which indicates that the empirical formula is also suitable for the prototype scale.

SiPM-based camera for gamma-ray imaging air Cherenkov telescope

The current status of the equipment development for the new wide-angle gamma-ray imaging air Cherenkov telescope for TAIGA hybrid installation is presented. A front-end electronic and data acquisition system board based on the Zynq family Xilinx FPGA chips specially designed for this project have been produced and are being tested. A detailed description if presented for internal structure of the four main subsystems: four 8-channel 100 MHz ADCs, board’s control system, internal clock and synchronization system and the power supply system. Additionally, the current status of a small scale prototype telescope SIT consisting of 49 SiPM is presented. The telescope includes a digital camera for observing the stars and weather condition. The SIT-HiSCORE synchronization systems and the telemetry information collection had been tested.

Development of a Collisional Radiative Model for Hydrogen-Cesium Plasmas and Its Application to SPIDER

SPIDER is the full scale prototype for the ITER Heating Neutral Beam (HNB) source. The production of negative ions in the source mostly relies on the conversion of H/D atoms and positive ions on a 1.6 m <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times0.8$ </tex-math></inline-formula> m converter surface, which is covered with cesium in order to reduce its work function and maximize the conversion efficiency. In SPIDER, optical emission spectroscopy (OES) is used to study the light emitted by the plasma. In particular, the intensities of the cesium emission lines are tracked and used to reconstruct the distribution of its excited states. By coupling these measurements with a collisional radiative (CR) model, estimates of the cesium ground-state density and plasma parameters can be obtained in various parts of the source which are unreachable by other diagnostics. This work describes such a model and its use in conjunction with OES during the first operation with cesium in SPIDER. The electron density at the bottom of the source was found to be much larger than the rest, as a consequence of vertical drifts caused by the horizontal filter field, which would likely indicate a lower negative-ion availability for the beam. The effect of increasing the cesium evaporation rate on the negative-ion and electron densities was also investigated.

An Adaptive-Gain Super-Twisting Position Observer for Grid-Interfaced SRM Water Pump

This work contributes for the development of a low-cost reliable switched reluctance motor (SRM) drive for domestic water supply requirements. The work presents an adaptive gain super twisting sliding mode observer (AGST-SMO) for SRM drive with an enhanced transient behaviour. An online updation of sliding gains is proposed while satisfying the stability conditions of the observer. Performance of this observer is compared with the existing sliding mode observers. The developed SRM drive has a dedicated-port configuration to integrate the sources with SRM-pump and a domestic equipment, with reliable operation at low cost. For grid-side power quality issues, an improved linear sinusoidal tracer (ILST) is employed for the control of voltage source converter (VSC). ILST has inherent merits like active harmonics filtering, power factor correction, and fast dynamic response. The control of the drive system is validated by developing laboratory scale prototype and the system performance is examined at different conditions. The drive is suitable to fulfil water requirements for various applications at the consumer-end.

Status of the SPHERE project for high energy cosmic ray studies by registering reflected Cherenkov light with a drone-borne detector

Here we present the current state of the technical design of the SPHERE project’s new detector. The SPHERE project is aimed at primary cosmic ray studies in the 1–1000 PeV energy range using the reflected Cherenkov light method. The concept of a drone mounted detector with a photosensitive camera based on silicon photomultipliers is discussed. The design details of a small scale prototype of this detector is presented.

Design of Horizontal Axis Wind Turbine Simulator Using Smart Monitoring System

Wind turbine shows the direct utilization of mechanical energy and occurs as follows: the wind that moves hitting the wing of the ferris wheel causes the ferris wheel to spin. The rotation of the ferris wheel causes the formation of mechanical energy, while the conversion of wind energy into electrical energy is as follows: the wind through the ferris wheel plants causes the ferris wheel to spin. The spin of the ferris wheel causes the generator to spin. Inside the wind energy generator is converted into electrical energy. In the Final Task that did the design of this prototype, do a comparison between the horizontal axis wind turbine with variations in the number of blades, with blade variations totaling 3 and 5. So, there will be 2 wind turbines with different numbers of blades in one prototype. Comparisons are made to find out the performance carried out by the two wind turbines that aim as a learning medium in the Measurement Instrumentation Laboratory. This final task is divided into five stages: including, tool design, tool characterization, tool validation, tool testing, and comparing tools. The process of designing tools that are divided into two methods, namely covering the formation of hardware and the formation of software. From the graph data contained in the discussion shows the performance with the propeller amounting to 5 produces a higher current and voltage output and rpm on this prototype scale than the number of propellers 3, with the value for example at the acceleration of fan 5 with a wind speed of 3.9 m / s on the propeller amounting to 5 resulting in an average current value of 3.2 mA, a voltage of 1.98 V, and rotor rotation of 234 RPM. While at the number of propellers 3 with the same wind speed produces smaller current output, voltage and rpm, which is obtained an average current of 2.3 mA, a voltage of 1.88 V, and rotor rotation of 243 RPM.