Search Results (798)

Particle-in-Cell (PIC) simulations require accurate solutions of the electrostatic Poisson equation, yet accuracy often degrades near irregular Dirichlet boundaries on Cartesian meshes. While prior work has focused on left-hand-side (LHS) discretization errors, the impact of right-hand-side (RHS) inaccuracies arising from charge deposition near boundaries remains largely unexplored. This study analyzes numerical errors induced by underestimated RHS values at near-boundary nodes when using embedded finite difference schemes with linear and quadratic boundary treatments. Analytical results in one dimension and truncation error analyses in two dimensions show that RHS inaccuracies affect the two schemes in fundamentally different ways: They reduce boundary-induced errors in the linear scheme but introduce zeroth-order truncation errors in the quadratic scheme, leading to larger global errors. Numerical experiments in one, two, and three dimensions confirm these predictions. In two-dimensional tests, RHS inaccuracies reduce the $L_{\infty }$ error of the linear scheme by a factor of 2–3, while increasing the quadratic-scheme error by several times, and in some cases by nearly an order of magnitude, with both schemes retaining second-order global convergence. A simple $\overline{\delta }$-based RHS calibration is proposed and shown to effectively restore the accuracy of the quadratic scheme. Full article

This study investigates the environmental and economic dynamics of sustainable aviation through the perspectives of senior executives in Türkiye’s civil aviation sector. As global aviation continues to face increasing pressure to decarbonize, understanding how industry leaders perceive and respond to carbon emission challenges is critical. The research employs a qualitative methodology based on semi-structured interviews with ten executives across airlines, airports, and aviation authorities. Using Python-based data mining techniques and thematic analysis, three core themes emerged: (1) sustainable aviation experience and economic dimensions; (2) carbon emissions reduction and efficient aviation systems; (3) sustainable energy and alternative fuel technologies. Findings reveal that while environmental sustainability is a growing concern, operational costs, technological constraints, and regulatory uncertainties significantly influence implementation. Stakeholders emphasized the importance of coordinated action among governments, industry, and international organizations, especially in scaling Sustainable Aviation Fuels (SAFs) and enhancing infrastructure for electric and hydrogen-powered aircraft. The study concludes that achieving net-zero aviation by 2050 requires an integrated approach that balances technological innovation, policy incentives, and stakeholder engagement. This multidimensional insight contributes to the ongoing discourse on low-carbon transition strategies in aviation, offering policy-relevant implications for developing countries. Full article

Designing cost-effective, reliable diagnostic sensor suites for complex assets remains challenging due to conflicting objectives across stakeholders. A holistic framework that integrates the Normalised Diagnostic Contribution Index (NDCI)—which scores sensors by separation power, severity sensitivity, and uniqueness—with a Multi-Objective Sensor Optimisation Framework (MOSOF) is presented. Using a high-fidelity virtual aircraft model coupling engine, fuel, electrical power system (EPS), and environmental control system (ECS), NDCI against minimum Redundancy-maximum Relevance (mRMR) is benchmarked under a rigorous nested cross-validation protocol. Across subsystems, NDCI yields more compact suites and higher diagnostic accuracy, notably for engine (88.6% vs. 69.0%) and ECS (67.7% vs. 52.0%). Then, a multi-objective optimisation reflecting an airline use-case (diagnostic performance, cost, reliability, and benefit-to-cost) is executed, identifying a practical Pareto-optimal ‘knee’ solution comprising 12–14 sensors. The recommended suite delivers a normalised performance of ≈0.69 at ≈USD36k with ≈145 kh MTBF, balancing the cross-subsystem information value with implementation constraints. The NDCI-MOSOF workflow provides a transparent, reproducible pathway from raw multi-sensor data to stakeholder-aware design decisions, and constitutes transferable evidence for model-based safety and certification processes in Integrated Vehicle Health Management (IVHM). The limitations (simulation bias, cost/MTBF estimates), validation on rigs or in-service fleets, and extensions to prognostics objectives are discussed. Full article

Urban Air Mobility (UAM) promises to reduce ground traffic and journey times by using electric vertical take-off and landing (eVTOL) aircraft for short, low-altitude flights, especially in urban environments. However, low-flying aircraft are at particularly high risk of collisions with wildlife, such as birds. This study builds on previous research into UAM collision avoidance systems (UAM-CAS) by implementing one such system in the BlueSky open-source air traffic simulator and evaluating its efficacy in reducing bird strikes. Several modifications were made to the original UAM-CAS framework to improve performance. Realistic UAM flight plans were developed and combined with real-world bird movement datasets representing typical birds in sustained flight from all seasons, recorded by an avian radar at Leeuwarden Air Base. Fast-time simulations were conducted in the BlueSky Open Air Traffic Simulator using the UAM flight plan, the bird datasets, and the UAM-CAS algorithm. Results demonstrated that, under modelling assumptions, the UAM-CAS reduced bird strikes by 62%, with an average delay per flight of 15 s, whereas 27% of the remaining strikes occurred with birds outside the system’s design scope. A small number of flights faced substantially longer delays, indicating some operational impacts. Based on the findings, specific avenues for future research to improve UAM-CAS performance are suggested. Full article

This article presents a comprehensive analysis of the primary electrical power distribution system in hybrid-electric aircraft, with particular emphasis on its environmental performance assessed through Life Cycle Assessment (LCA). High-resolution Life Cycle Inventory (LCI) data were developed in collaboration with industry partners and refined to reflect current production standards. The results indicate that printed circuit boards (PCBs), magnets, precious metals (gold and silver), and copper are the primary contributors to environmental impact, with PCBs alone accounting for over 50% of material-related emissions. Although precious metals constitute only 0.014% of the product’s mass, they account for nearly 9% of total emissions due to the energy-intensive nature of their mining and refining processes. Additionally, manufacturing stages involving thermal treatments—such as surface coating of iron cores at 850 °C for 14 h—significantly increase energy consumption and associated emissions. The study concludes with recommendations for reducing the carbon footprint of future aircraft power systems through improved material efficiency, process optimization, and supply chain sustainability. Full article

Multifunctional aerostructures that carry mechanical loadings while conducting electrical currents offer a promising approach to reduce the weight of Electrical Power Systems (EPS) of aircraft. However, Carbon Fibre-Reinforced Polymer (CFRP), when used for aerostructures, presents challenges in achieving multi-functionality due to anisotropic mechanical, electrical, and thermal properties. These properties are interdependent on both laminate-level design factors (fibre/resin choice, fibre volume fraction, stacking sequence, and electrode configuration) and system-level EPS constraints (allowable voltage drop, current, and installation geometry). State-of-the-art material design and selection methods lack a coupled mechanical–electro–thermal design and selection approach to overcome these challenges of a complex design space to enable identification of multifunctional CFRP (MF-CFRP) solutions. This paper presents the first methodology for the design and selection of MF-CFRP with combined electrical, structural, and thermal properties. The methodology integrates requirement capture, laminate layup determination, electro-thermal assessment, option ranking, and manufacturing route selection. The methodology couples laminate-level design factors with system-level EPS constraints and includes iterative loops to refine either the CFRP design or the EPS parameters when no solution initially exists. The methodology is demonstrated to enable the design of a CFRP component to conduct the electrical current as part of the 28 V_DC network in an aircraft. This case study demonstrates the value of the methodology to identify knowledge and dataset gaps necessary for MF-CFRP design, alongside enabling the design of MF-CFRP components to enable increased power density of weight-critical EPS. Although the case study focused on a 28 V_DC system, the methodology is generalisable to other aircraft electrical architectures since system-level electrical parameters are used within the methodology as adaptable inputs. Full article

High-Frequency (HF) geolocation is crucial for emergency search and rescue operations and for re-geolocation of missing targets. This paper proposes a two-stage (Receiver selection then geolocation with Random Spatial Spectrum (RSS)) framework with HF skywave propagation as the main link, which is suitable for scenarios where the electric Vertical Take-off and Landing (eVTOL) aircraft loses contact, crashes, or has communication interruption after a malfunction. First, stage A employs two receiver selection paths. One is selection with unknown biases, which combines geometric observability to determine receiver selection. The other is selection with bias priors, which introduces non-line-of-sight bias priors and robust weighting to improve availability. Secondly, stage B constructs RSS-based geolocation using grid objective function matching to alleviate the sensitivity of explicit time difference estimation to noise and model mismatch, thereby maintaining robustness under non-line-of-sight (NLOS) conditions. Finally, simulation and actual measurements demonstrate that the “select first, geolocation later” approach achieves superior overall performance compared to direct geolocation without receiver selection. This study provides a methodological basis and initial field evidence for HF skywave-based emergency eVTOL geolocation. Full article

To explore the potential of solar energy in the pursuit of a more sustainable aviation sector, this research examines the feasibility of solar photovoltaic systems for battery recharge of electric or electric hybrid aircraft deployed at four airports in North Africa and North, Central, and South Europe, respectively: Cairo International, London Heathrow, Milan Malpensa, and Rome Fiumicino. Employing PVGIS software with Google Maps, a site-specific photovoltaic array can be designed, optimizing module tilt and orientation to maximize solar energy collection across various climatic conditions. The energy production of the photovoltaic systems at the selected airports is compared to the energy demand required for the annual recharge of the batteries (28 MWh each) used in a widely popular medium-range aircraft, the Airbus A320. Although the calculated amount of energy, allowing for daily capacities ranging from 6 to 10 batteries on average, is insufficient to support the extensive demand associated with the typical air traffic in such airports, the potential of solar energy to decarbonize aircraft seems an appropriate approach to be pursued. Locations with limited solar access necessitate hybrid solutions, especially in sunny regions. Full article

The development of solar-powered UAVs offers major advantages, such as extended mission autonomy, marking a significant technological advance in the aerospace industry. In this context, the study demonstrated the feasibility of additive manufacturing of a solar-powered UAV by successfully completing all the steps necessary for the development of an aeronautical product. The conceptual design was the initial phase in which the needs were defined, and the basic vision of the UAV model was outlined, exploring multiple possible solutions to identify the concept capable of meeting the mission requirements (search and rescue and surveillance). The preliminary design stage included aerodynamic analysis of the aircraft and preliminary sizing of the propulsion system and solar cells. The preliminary design stage included aerodynamic analysis of the UAV model, resulting in a lift coefficient of 1.05 and a drag coefficient of 0.08 at an angle of attack of 15°. A major advantage of the design is the integration of the electrical circuit, where solar input reduced battery consumption from 92.5 W to just 40.4 W in standard operational conditions, thereby more than doubling the UAV’s autonomy (from 48 min to approximately 110 min). The detailed design stage consisted of the final design of the solar UAV model for additive manufacturing, after which the final electrical architecture of the energy system was established. The model was subsequently validated by a finite element analysis, which confirmed the strength of the wing structure by achieving a safety factor of 6.6. The use of additive manufacturing allowed the rapid and accurate production of the structural components of the UAV model, ensuring that their subsequent physical assembly would be straightforward. Full article

Advances in distributed electric propulsion and urban air mobility technologies have spurred a surge of research on electric Vertical Take-Off and Landing (eVTOL) aircraft. Distributed Multi-Propeller Tilting-Wing (DMT) eVTOL configurations offer higher forward flight speed and efficiency. However, aerodynamic challenges during the transition phase have limited their practical application. This study develops a high-fidelity body-fitted mesh CFD numerical simulation method for flow field calculations of DMT aircraft. Using the reverse overset assembly method and CPU-GPU collaborative acceleration technology, the accuracy and efficiency of flow field simulations are enhanced. Using the established method, the influence of dynamic tilting speeds on the flow field of this configuration is investigated. This paper presents the variations in the aerodynamic characteristics of the tandem propellers and tilt-wings throughout the full tilt process under different tilting speeds, analyzes the mechanisms behind reductions in the propeller’s aerodynamic performance and tilt-wing lift overshoot, and conducts a detailed comparison of flow field distribution characteristics under fixed-angle tilting, slow tilting, and fast tilting conditions. The study explores the influence mechanism of tilting speed on blade tip vortex-lifting surface interactions and interference between tandem propellers and tilt-wings, providing valuable conclusions for the aerodynamic design and safe transition implementation of DMT aircraft. Full article

Air travel contributed 3.5% to global warming in 2020, with a rising tendency. Only one third of the climate impact is caused by CO₂. Other exhaust gases that cause harm to the climate are nitrogen oxides, soot, and water vapor, creating contrails with a negative impact on earth’s albedo. Hence, it is important to reduce any type of emission. As the effects of global climate change become an unneglectable threat to society, calls for quick changes become prominent. Recognizing the need for disruptive changes in air transport, the LuFo-project 328eHY-TECH was initiated to investigate the potential of regional hybrid-electric aircraft. This article focuses on conceptual aircraft design. An aircraft resembling the D328eco is modeled as a baseline aircraft, on which the sizing of the hybrid-electric propulsion systems is performed. As aircraft are mostly operated on a typical mission, which is shorter than the design mission, a distance of 400 nm is found to be a feasible range for this regional aircraft. In a conducted range study, the potential of state-of-the-art battery properties is being investigated and found to be insufficient. Subsequently conducted trade-off studies show that a 104 kW horsepower electric motor and a battery of 1.8 kWh/kg are needed to save 5% block fuel on a mission with 40 passengers of 95 kg over a distance of 400 nm. It is concluded that changing solely the propulsion system will not yield feasible aircraft designs in the near and midterm future. Full article

With the development of distributed electric propulsion aircraft, researching airborne high-efficiency, high-power-density, high-gain, high-dynamic and low-ripple, low-stress DC-DC that meets aviation standards is an urgent and profoundly challenging task (Research Background). We propose a new topology to implement related applications. The new topology consists of an interleaved switched-inductor unit for a high-gain, low-ripple, and high-dynamic response, and a switched-capacitor unit for secondary boosting and low voltage stress. This study first analyzes in depth the operating principle and electrical characteristics of the proposed topology in different modes, showing that the proposed topology can achieve an extremely high voltage gain while maintaining low voltage stress. Moreover, the proposed topology employs interleaved inverse coupled inductors to eliminate right-half-plane zero (RHPZ). We establish a universal design guideline for coupled inductors by deriving the equivalent inductance equations, and we implement an ultra-lightweight switched-coupled inductor using planar thin-film integrated magnetic technology. We conduct small-signal modeling to verify the loop characteristics and stability of the proposed converter. Finally, the correctness of the theoretical analysis and the advantages of the proposed converter were verified through a 5000 W experimental prototype and comprehensive comparative experiments. Full article

This paper presents the design, optimization, and validation of a dual three-phase yokeless and segmented armature (YASA) axial flux permanent magnet (AFPM) machine for aerospace actuators. The proposed 12-slot, 10-pole topology employs segmented soft magnetic composite (SMC) stator teeth integrated into an additively manufactured aluminium holder, combining modularity, weight reduction, and improved thermal conduction. A multi-objective optimization process based on 3D finite element analysis (FEA) was applied to balance torque capability and losses. The manufacturable design achieved a peak torque of 28.3 Nm at 1400 rpm and a peak output power of 3.5 kW with an efficiency of 81.6%, while limiting short-circuit currents to 14 Arms. Transient structural simulations revealed that three-phase short circuits induce unbalanced axial forces, exciting rotor wobbling—a phenomenon not previously reported for YASA machines. A prototype was fabricated and tested, with static torque measurements deviating by 8.6% from FEA predictions. By contrast, line-to-line back-EMF and generator-mode power output exhibited larger discrepancies (up to 20%), attributed to the frequency-dependent permeability and localized eddy currents of the SMC stator material introduced during EDM machining. These results demonstrate both the feasibility and the limitations of YASA AFPM machines for aerospace applications. Full article

The transition to electric aircraft for zero-emission transport requires integrating thermal management systems for high-performance batteries without incurring significant weight, balance, or aerodynamic penalties. This study focuses on the aerodynamic penalties associated with air-cooling systems that can compound the presently unavoidable reduction in endurance imposed by current battery energy density limitations. Building on previous research into battery installation layouts and internal cooling flows, this study is the first to investigate the lift-to-drag (L/D) optimisation for the multiple wing-mounted inlets and outlets necessary for air-cooling batteries in the wing of an electrified aircraft. Wing leading-edge inlets and NACA (National Advisory Committee for Aeronautics) ducts were analysed by systematically varying their layout, number, and dimensions. The analysis evaluated their effects on the wing’s lift, drag, and moment to maximise the L/D. Multiple highly efficient simulation test designs were developed to screen for the main factors to identify the best inlet and outlet configuration, resulting in 66 different Computational Fluid Dynamics (CFD) simulations in Ansys Fluent. Following this, three CFD verification cases of the best configuration were conducted to verify the cooling effect by combining both internal and external flow simulations with heat generation. Compared to the baseline wing of the carbon combustion aircraft, the best configuration caused a 1.75% reduction in L/D, range, and endurance. While the aerodynamic penalty is now minimised, the internal battery pack layout requires further optimisation to re-establish uniform cooling across the battery pack. Designers may still be able to separate the CFD analysis of the internal and external flow regimes with idealised inlets and outlets; however, more whole-field CFD iterations are needed to guide such subdivision to a viable and safe design for wing-mounted batteries. Further, the margins are such that wing-mounted electrification warrants careful instrumented validation in an aircraft. These findings provide crucial design guidance for sustainable aviation, particularly to enable after-market electrification projects. Full article

To meet the sustainable development goals of the aviation industry, promoting digitalized all-electric aircraft (AEA) is a critical path. However, during the dynamic popularization process of digitalized AEA, the interests among manufacturers, airlines, and governments vary, coupled with a notable time delay in digitalized technological R&D and market promotion. Therefore, this study establishes differential game models for popularizing AEA and investigates dynamic optimal strategies of potential benefits, levels of digitalized R&D, consumer preferences, and market demand, under three game modes: Nash non-cooperative, cost-sharing, and collaborative cooperation. The research finds that: (1) When the promotion cost of AEA is lower than a certain threshold, the cost-sharing model can effectively enhance digital R&D. (2) In the case of ignoring time lag, the initial value of the battery life level and consumer preference becomes the decisive factor that significantly affects its dynamic evolution trajectory. Under the cost-sharing model, the battery life level and consumer preference reached 107.13 and 15.26, respectively. This is significantly higher than the collaborative model and the NASH non-cooperative model. (3) When the delay effect exceeds the thresholds of 4.58 and 5.49, respectively, the Nash non-cooperative model becomes the most effective promotion model. This paper provides an important decision-making reference for promoting the digital transformation and sustainable development of the aviation industry. Full article