Dassault Systèmes (Germany)

In this work, we present an innovative approach to enhance multiband communication systems by enabling the antenna subsystems to simultaneously transmit and receive across multiple independent in-band full-duplex (IBFD) channels, i.e. multiband-IBFD (MIBFD). This capability is powered by fractal antenna arrays, specifically using hexagonal star array (HSA) geometry. The approach provides a unique self-interference cancellation (SIC) capability across multiple bands (MB-SIC), achieved through translation or rotational transformations of self-similar or self-affine array structures. Simulation results demonstrate significantly enhanced SIC bandwidth for three signals at sub-frequencies near 5 GHz, with the integration of subbands’ SIC bandwidths achieving 1.4 GHz across these subbands. Further enhancements include combining this method with a technique involving the elevation of the central receiving element, significantly broadening the SIC bandwidth compared to traditional methods. Additionally, the multiband functionality is validated with pilot signals at 2.68 and 5.2 GHz, showing effective SIC in these narrow bands. This research presents a promising path for optimising radio resources in multiband communication systems.

Climate Change and Materials Criticality challenges are driving urgent responses from global governments. These global responses drive policy to achieve sustainable, resilient, clean solutions with Advanced Materials (AdMats) for industrial supply chains and economicprosperity. The research landscape comprising industry, academe, and government identified a critical path to accelerate the Green Transition far beyond slow conventional research through Digital Technologies that harness Artificial Intelligence, Smart Automation and High Performance Computing through Materials Acceleration Platforms, MAPs. In this perspective, following the short paper, a broad overview about the challenges addressed, existing projects and building blocks of MAPs will be provided while concluding with a review of the remaining gaps and measures to overcome them.

The goal of this paper is to deepen our fundamental knowledge of rotor aeroacoustics in transitional boundary layer regimes and, more specifically, in the presence of a laminar separation bubble. A numerical study is conducted by using a scale-resolving wall-modelled lattice Boltzmann solver and the same reference configuration used in our previous works. The main focus of the present research is on the effects due to test-room confinement, and consequent flow recirculation, on the noise generated by the rotor in hover and in axial flow conditions. This new effort follows our hypothesis of inflow disturbances altering the mechanism of the laminar separation, and thus responsible for the broadband noise prediction discrepancy previously observed in hover conditions in free-field. Simulations carried out in a confined environment that reproduces the A-Tunnel test chamber of Delft University of Technology refute our initial hypothesis. Conversely, simulations with increased mesh resolution along the blade leading edge compare more favorably with the experiments. Therefore, we conclude that, for the considered configuration, the room confinement does not affect the laminar separation bubble mechanism, but causes the emergency, in hover conditions, of harmonics of the blade passing frequency. As a secondary outcome of this work, a source identification technique based on the acoustic analogy approach is presented for the first time.

Societal Challenges demand for Advanced Materials, which in turn promise economical potential. Material Acceleration Platforms (MAPs) will decrease their development time and cost. We comment on implications for science, industry and policy concluding with necessary steps towards establishment of MAPs.

Multi-temporal quantification of surface change DatasetsWe used large format aerial imagery surveyed by the Bundesamt für Eich-und Vermessungswesen (BEV); the Landesamt für Digitalisierung, Breitband und Vermessung (LDBV); and the company 3D RealityMaps.Detail information on the aerial surveys is listed in Table 1.Table 1.

This work presents a multi-fidelity framework for wind-turbine aeroacoustic simulations developed at Dassault Systemes. The framework is based on concurrent semi-analytical aerodynamic/aeroacoustic calculations and scale-resolving Computational Fluid Dynamic (CFD) simulations, the latter performed by considering two-dimensional extruded blade profile calculations and three-dimensional full wind-turbine calculations, respectively. Flow simulations are performed by using the high-fidelity multi-propose CFD software SIMULIA PowerFLOW. The benchmark wind-turbine NM80 configuration is considered initially for the assessment of the methodology, while the focus of current paper is on the prediction of wind-turbine serrated blade trailing-edge noise from 2.5D blade section CFD simulations. A step-by-step engineering approach is applied, leading to the analysis and optimization of serrated trailing-edges at different radial positions. Results between airfoil trailing-edge noise prediction in wind-tunnel quasi two-dimensional conditions and the full three-dimensional rotating turbine are compared, confirming lower level of far-field noise reduction for the latter compared to the former, and thus revealing the importance of the proposed methodology in the framework of digital noise reduction prediction of full-scale serrated wind turbine blades.

View Video Presentation: https://doi.org/10.2514/6.2023-1683.vid Throughout the design process of an aircraft, structural models are built at different levels of the system. In early phases, coarse representations of the full vehicle structure are used for initial sizing activities while refined models of sub-systems are built in later phases for detailed sizing. Load data is typically generated at full vehicle level and must be accurately transferred and applied to detailed models of sub-systems. Often it is challenging to synchronize all models involved in the process with the latest design data since the models are built in a disconnected manner. To address these challenges, we propose a unified workflow in this paper that connects structural models at different system levels and enables seamless load transfer while ensuring associativity with parametric design data. In the development of electric vertical take-off and landing (eVTOL) vehicles for Urban Air Mobility, lightweight design is of particular importance to compensate for the additional weight that is brought into the vehicle through batteries. Therefore, the unified workflow proposed in this paper is demonstrated in the context of Urban Air Mobility. We show how a conceptual model of a full eVTOL vehicle and a detailed model of its wing are built and associated with a parametric design model. The focus is then on detailed sizing of the wing structure driven by load data from the full vehicle model. A design exploration study for the wing structure aiming at meeting requirements in terms of skin buckling is performed and the best alternative is validated through a detailed post-buckling simulation.

The World Health Organization has pointed out that airborne transmission via aerosol particles can be a strong vector for the spread of SARS-CoV-2. Protecting occupants from infectious diseases or harmful particulate matter (PM) in general can be challenging. While experimentally outlining the detailed flow of PM in rooms may require complex setups, computational fluid dynamics (CFD) simulations can provide insights into improving the safety of the built environment and the most effective positioning of air-purifying devices. While previous studies have typically leveraged Reynolds-averaged Navier–Stokes (RANS) approaches for predicting particle propagation, the turbulence length scales accurately captured in these simulations may not be sufficient to provide a realistic spread and the mixing of particles under the effects of forced convection. In this paper, we experimentally validate a Lattice Boltzmann very large eddy simulation (VLES) approach including particle modeling. We also demonstrate how this simulation approach can be used to improve the effectiveness of air filtration devices in realistic office environments.

Size optimization of medium voltage (MV) devices, such as switchgear, requires accurate prediction of the impulse and AC power frequency breakdown voltages which is the focus of the paper. Dielectric breakdown was performed on three electrode arrangements that simulate actual switchgear for SF6 and two fluoronitrile/CO2 mixtures and the experimental data were compared with simulation result based on the streamer inception criterion. For weakly non-uniform fields, the experimental values show good agreement with those predicted using an approximation formula for the effective ionization coefficient. For strongly inhomogeneous fields, the breakdown voltage is computed based on the non-uniformity factor. A framework rule for breakdown prediction based on the streamer criterion, when applied to several switchgear electrode designs and gases, show good agreement with experimental results.

In order to ensure structural integrity, Urban/Advanced Air Mobility (UAM/AAM) vehicle manufacturers are required to perform fatigue and damage tolerance (F&DT) studies across design, manufacturing, and in-service stages. There is high chance that these vehicles will be made of composites, wherein different defects can occur during manufacturing and while the vehicle is in service. Finite Element Analysis (FEA) can be used to understand the effect of defects on structural performance and build better confidence for certification. In this paper, a methodology is proposed to model pre-existing defects in an existing structural analysis with the use of templates. Such templates provide an accessible packaging of the modeling and simulation methods to various analysts. Damage tolerance analysis done in this way helps in quickly evaluating acceptable composite defect type and size and easily shares modelling expertise among all users.